[LeoTaylor]

Going back to my list of combinations of Tracking and Guiding. Someone may wonder why there wasn't a No Yes example. Well, if you do not have tracking of the 15 degrees per hour rotation of the Earth the guider would have a heck of a time keeping up with that and still fixing the small stuff it was intended for. Basically the tracking should keep the heavens reasonably still on the camera's sensor. Guiding adds the extra adjustments to keep it steadier in the short run and hold that position for a long time.

My unguided DSLR/telescope images do not drift enough in 120 seconds to produce elongated stars. They do slowly drift along but the Images Plus software can handle that when stacking. The same is true for my unguided DSLR/camera lens images on a portable mount, they do not drift enough in 30 seconds to produce elongated stars.

[pti-andy]

OK, that makes more sense, I was trying to wrap my head around the concept! So you basically go from wide field tripod shots at reasonably long shutter speeds (15-20 secs or so for a 24mm lens?) to motorized tracking without guiding, to motorized tracking using a separate (and I presume mounted together with the camera) guide scope keeping some point of reference in a fixed position so that you know you're maintaining target... I guess the only thing you really worry about is Earth's rotation and not any other sort of movement.

Not much more to add to Leo's comprehensive explanation. You pretty much got it down already. To sum it up, the longer the folcal length, the more the need for a tracking mount, or the more critical the guiding becomes when using a tracking mount. I'd like to reiterate a point that Leo touched on and that is if your equipment get's large enough you will start to get flexure between the guide scope and the lens your photographing through. This will introduce errors as the mount rotates and the equipment weight shifts since the guider won't see the other scope shifting. This will ruin even perfectly guided shots which is why it is so important to have a good mounting system.

And yes the software to follow a star is not trivial but not particularly mind bending either. I have written said software for a webcam application but never driven the ST-4 pins themselves.

Wow, Jack, writing your own guiding software is impressive. Do you have plans to sell it or put it out in shareware? Do you have any samples of your work?

When we move overseas in the spring we will be in a fairly dark area in Sweden, so would like to invest in a decent setup for both observation and astrophotography at that point. With a budget of say $3k, what would you guys recommend? I have a good camera (50D) already so should be ok at least for hobby purposes.

I'd check out Losmandy Astronomical Products for a mount. For the money they can't be beat and you can get a really good start for the budget your talking about. I have a GM8 right now which works great for light to medium weight equipment but will probably upgrade to a G11 for prime focus shots through a telescope. The GM8 just can't handle the weight well and limits me to large telephoto lens work by the time I add up the weight of the lens and guidescope.

Yes, there are a lot of DSOs on my web site, mostly galaxies. These were the objects I was most fond of and the ones my little SBIG was best at. With my SCT, location, and K1000 I was limited to eight galaxies. In 2000 I bought an SBIG and as you can see I have exceeded 25 galaxies in one tiny frame. I imaged galaxies as fast as I could.

You are too kind in your comments about my observatory. My friend's observatory in the Berkshires cost more for one Astro Physics 1200 mount (list price $9800) then all my equipment together. but he takes far better photos.

I'm glad you did not have amp-glow with the new camera. A red area in the upper left quashed my hopes to use a istD for non-nebula astro. My Modified K110D is a poor choice for stars since it is near impossible to get the red out. In hind sight I should have brought a K100D to the dark site since the color would be more natural. I made another mistake, I'm so used to using an IDAS light pollution filter I took all 9 hours with an LP filter at a place that did not need it. The LP filter tinges the colors toward blue. At 3 AM my friend asked, "Why did you use an LP filter on a night like this?" I did not have a good answer! So I have some tough color correction to deal with.

I really got a chuckle out of the flower pot as I was reading your site. I thought it was a very engenius and humerous way to solve that problem.

I like your Galaxy shots. Since you also shoot from a rural site and are limited like I am, what would you consider to be the top 10 brightest or easiest Galaxies and nebula for our areas?

You should really try a K-x. I use to shoot with a K100DS, then a K200D and both of them had really bad amp glow and chroma noise. I am finally now not limited by the camera and am going to upgrade to some more serious guiding gear.

-Andy

[Ash]

Brilliant results Andy.
I've never seen such crisp results as you've produced here.
Good to see Pentax has finally produced a camera suited to your application!
Thanks for sharing these fine examples.

[LeoTaylor]

I like your Galaxy shots. Since you also shoot from a rural site and are limited like I am, what would you consider to be the top 10 brightest or easiest Galaxies and nebula for our areas?

You should really try a K-x. -Andy

I'm in a semi-urban location, The city of New Haven starts 1/4 mile South. So my Southern exposure where I find most objects is over a city close to 100,000. There are Summer nights when I can't see Sagittarius and I know it is right in front of me.

Ten easy Galaxies must include those I could do with film: M31/32, M65/66, M81/82, M51/NGC 5195. After I went digital I soon added NGC 891, NGC 4565.

I'll consider a K-x. I could use a present this season. I need to read up on its live modes. I envy the newer cameras that can focus and video while holding the mirror up. Canon's Live View changed the playing field for Planetary and Satellite imaging. My K110D faithfully performs when I take images as fast as it will go during a pass of the International Space Station. But I know the shutter is not designed to go KerChunck, KerChunck that fast for that long.

Perhaps I'll wait until the K-x price goes down after they introduce the KY-J.

ISS imaged with K110D, Meade SCT and Barlow = 4000mm f20. March 17 with Shuttle Discovery docked at the station. The shuttle shows up as a dark delta wing since we are looking at the underside which has the heat tiles.

Attached Images

   

[LeoTaylor]

OK, you win, I'm seriously considering buying a K-X. I don't know why I'd spend this much on a DSLR, I have too many already. I keep saying I have to watch my budget since I'm retired. Now I'm thinking about spending more money on cameras. Perhaps I'll sell a K100D to alleviate the pain.

I downloaded the manual from Pentax. I found a nice data sheet that even has some details not in the manual and puts everything in a nice compact form. Only problem: it is written in Australian.

A few questions I have remaining:

The Data Sheet lists a Body Only version, how come the places I searched won't sell it without at least a kit lens? I love B&H and their lowest price is $599 with the 18-55. I just sold an extra kit lens, I'd rather not be pushed into buying another.

The weird AC supply (which I must have) is the K-AC84 which costs $64. It contains a D-AC76 ($50) which is the same supply I use for all my DSLRs and a DC-84 coupler which I can't find anywhere. Does anyone know where I can buy a DC-84 which appears to be all I need to connect my existing supplies to the new camera? Boy do I wish the K-x had a jack on the side like everyone else. I connect the cables in the dark most of the time. I suppose I can plug in the DC-84 indoors leaving the short cord dangling then connect to the Pentax 6.5 volt supply I already have in the observatory.

Since the K-x requires you remove the batteries to use AC I wonder how long it will run without losing configuration. I think the K100D runs battery-less quite awhile.

The 1-AVC7 ($9.95) video cable look similar to the K100D video cable, does anyone know if can use my existing video cables?

Just to make sure, is it true that with Live View I can connect the telescope mounted K-x to my observatory's video monitor (an old analog 13 in TV) and focus in real time? No longer will I need to take a shot, wait for it to save, press Play, look at monitor, adjust, repeat.

I'm a bit concerned with how bright Live View will be. With my K100D I take 1-7 second focus images depending on the bright stars available. I hope I can see something on the screen with Live View. PTI-ANDY, have you pointed Live View at a night sky and seen at least a few stars?

I'm seeing the usual lack of software. The included disk does not seem to have Remote Assistant and neither does the Pentax Web Site. I've suffered from the lack of R.A. for the K1X0D, I hope there will be better support for the K-x. This can be a deal breaker, Winter is coming and I'd like to be able to see images download to the observatory computer which I can connect to from the warm house. A deal solver could be the extra, "PC Mode." in the K-x. My K110D can appear as a disk drive on the PC but the shutter jack goes dead. Does the K-x, "disk mode" keep the shutter jack active while appearing as a disk drive to the PC?

Finally, I have yet to find if the 1280*720 video mode uses the full with of the sensor (either by skipping pixels or binning) or if they only use the center 1/3 of the sensor. This makes a difference in Satellite Photography since keeping the image on sensor is much easier with a large sensor (eg APS-C 24mm) vs the tiny sensors in video cameras.

I'm thinking of purchasing on Black Friday weekend if the prices drop.

[pti-andy]

Brilliant results Andy.
I've never seen such crisp results as you've produced here.
Good to see Pentax has finally produced a camera suited to your application!
Thanks for sharing these fine examples.

Thanks. Actually the processing on them was quite hurried so they are a bit over processed and saturated with false color. Since then I have redone the processing and they look more realistic now with more detail. Once I get a clearer night I'll spend more time and they should be even better.

Ten easy Galaxies must include those I could do with film: M31/32, M65/66, M81/82, M51/NGC 5195. After I went digital I soon added NGC 891, NGC 4565.

ISS imaged with K110D, Meade SCT and Barlow = 4000mm f20. March 17 with Shuttle Discovery docked at the station. The shuttle shows up as a dark delta wing since we are looking at the underside which has the heat tiles.

Thanks for the galaxy info. The ISS shot is amazing! How were you able to track it with so much focal length? I've watch it go across the sky and it is really moving.

A few questions I have remaining:

The Data Sheet lists a Body Only version, how come the places I searched won't sell it without at least a kit lens? I love B&H and their lowest price is $599 with the 18-55. I just sold an extra kit lens, I'd rather not be pushed into buying another.

The weird AC supply (which I must have) is the K-AC84 which costs $64. It contains a D-AC76 ($50) which is the same supply I use for all my DSLRs and a DC-84 coupler which I can't find anywhere. Does anyone know where I can buy a DC-84 which appears to be all I need to connect my existing supplies to the new camera? Boy do I wish the K-x had a jack on the side like everyone else. I connect the cables in the dark most of the time. I suppose I can plug in the DC-84 indoors leaving the short cord dangling then connect to the Pentax 6.5 volt supply I already have in the observatory.

Since the K-x requires you remove the batteries to use AC I wonder how long it will run without losing configuration. I think the K100D runs battery-less quite awhile.

The 1-AVC7 ($9.95) video cable look similar to the K100D video cable, does anyone know if can use my existing video cables?

Just to make sure, is it true that with Live View I can connect the telescope mounted K-x to my observatory's video monitor (an old analog 13 in TV) and focus in real time? No longer will I need to take a shot, wait for it to save, press Play, look at monitor, adjust, repeat.

I'm a bit concerned with how bright Live View will be. With my K100D I take 1-7 second focus images depending on the bright stars available. I hope I can see something on the screen with Live View. PTI-ANDY, have you pointed Live View at a night sky and seen at least a few stars?

I'm seeing the usual lack of software. The included disk does not seem to have Remote Assistant and neither does the Pentax Web Site. I've suffered from the lack of R.A. for the K1X0D, I hope there will be better support for the K-x. This can be a deal breaker, Winter is coming and I'd like to be able to see images download to the observatory computer which I can connect to from the warm house. A deal solver could be the extra, "PC Mode." in the K-x. My K110D can appear as a disk drive on the PC but the shutter jack goes dead. Does the K-x, "disk mode" keep the shutter jack active while appearing as a disk drive to the PC?

Finally, I have yet to find if the 1280*720 video mode uses the full with of the sensor (either by skipping pixels or binning) or if they only use the center 1/3 of the sensor. This makes a difference in Satellite Photography since keeping the image on sensor is much easier with a large sensor (eg APS-C 24mm) vs the tiny sensors in video cameras.

I'm thinking of purchasing on Black Friday weekend if the prices drop.

I've never seen the K-x without Kit lens unless someone on ebay was parting it out.

I'd also like to get the DC-84 but I can't find anyone who sells it. I'll continue my search and you let me know if you see one somewhere.

I've only had batteries out of my K-x for five minutes so I know it will go that long but havn't tried any longer.

The K-x uses the same usb style connector so the video cable should be the same for all Pentax cameras.

Live View only works on bright stars but that is enough for live focusing. It tends to flicker a bit but it sure beats the "click and tweak" method.

Remote Assistant is not supported on the K-x and it does not have a remote shutter jack so this could be a deal buster for you since there is no way to start the exposure without the IR remote. I was thinking of making a remote shutter by taking apart a remote F and connecting a jack to the trip button. Then mount the remote on the tripod and now you can control it with all the fancy timers and gear that's out there. Either that or wait until Pentax makes a K200D replacement with this sensor.

The vield of view is the same in movie mode as normal mode so I would assume it would be using all of the sensors area or else it would be cropping the frame.

There are many limitations of the K-x in terms of controlling it and I've been able to get around most of them but the worst is the mandatory DFS for longer than 30s. There is just no reason for this. Even so with all of the limitations the sensor just can't be beat and is worth it even with 30s exposures.

-Andy

[LeoTaylor]

Thanks for the galaxy info. The ISS shot is amazing! How were you able to track it with so much focal length? I've watch it go across the sky and it is really moving.

I use software called Satellite Tracker, free from the Yahoo Group by the same name. It is challenging but can be done. I had to buy a joystick, only $15, but I've had a home computer since 1976 and never owned a joystick!

I've never seen the K-x without Kit lens unless someone on ebay was parting it out.

They seem to assume this will be your first camera. My wife bought the first Pentax K1000 in this house about 16 years ago. I bought her the 50mm f2 lens to go with it and we have been buying only K-mount lenses ever since.

I'd also like to get the DC-84 but I can't find anyone who sells it.

B&H sells the whole K-AC84 power kit. I suppose I could put the extra AC adaptor indoors for use when doing sensor cleaning, firmware updates, etc. Plus I'm occasionally stealing the observatory supply to go out in the field.

I've only had batteries out of my K-x for five minutes so I know it will go that long but haven't tried any longer.

I think it should retain setup long enough.

The K-x uses the same usb style connector so the video cable should be the same for all Pentax cameras.

I was stunned when I found the istD has different Power and Video cables then the K1x0Ds. I bought the istD for my wife as soon as it was introduced. She never used the cables so they got lost. When I needed them for astro I found one in the basement but had to buy the other. Then I found the istD has wicked amp glow and could not do astro.

Live View only works on bright stars but that is enough for live focusing.

Sounds good. I use Bahtinov masks, I hope Live View on a large monitor will be bright enough.

Remote Assistant is not supported on the K-x

Pentax supported the istD, K10, K20 so far. When the K100D came out many assumed it would be supported eventually, but it never was.

and it does not have a remote shutter jack so this could be a deal buster for you since there is no way to start the exposure without the IR remote.

That is very unfortunate. It is also why I ask questions since the manual does not tell you what the camera does not have that all predecessors did have. I looked for a photo of the connector arrangement, but did not see one. They do have a jack for video and USB. This discovery gives me pause....

I was thinking of making a remote shutter by taking apart a remote F and connecting a jack to the trip button.

I have two serial to 2.5mm plug shutter cables. One, relay based for the observatory computer. The other, opt-isolator based for my laptop. I suppose I could open up the IR device and find its switch contact. Talk about lost, I have not seen an IR remote since I bought the first K100D. Perhaps I should work on that before Black Friday since failure building a remote makes the K-x pretty useless to me. BTW: Some Nikons are the same way and companies make IR remote adaptors for them.

The field of view is the same in movie mode as normal mode so I would assume it would be using all of the sensors area or else it would be cropping the frame.

I think you are correct, if the FOV is the same they are not just using the center 1280 pixels. I wonder if they do binning which would increase sensitivity?

There are many limitations of the K-x in terms of controlling it and I've been able to get around most of them but the worst is the mandatory DFS for longer than 30s.

That I can live with. I actually use internal NR with the K1x0Ds. I know I lose 50% of my imaging time but I get better results in my light polluted location. With the SBIG I used Dark, Flat, Bias, and Flat-Dark frames. With the Pentax I use Flats.

Thank you for all your answers about this new camera.

[UnknownVT]

I've never seen the K-x without Kit lens unless someone on ebay was parting it out.

The Kx is available as body only, from reputable vendors -
please see this concurrent thread -

Best deals on K-x (body only or w/18-55)

The best Kx body only deal so far seems to be from Newegg at $599 with 10% Bing Cashback on Black Friday only.

[LeoTaylor]

The Kx is available as body only, from reputable vendors -
please see this concurrent thread -

Best deals on K-x (body only or w/18-55)

The best Kx body only deal so far seems to be from Newegg at $599 with 10% Bing Cashback on Black Friday only.

The K-x I found from B&H is $599 with 18-55 lens and before Black Friday. One would be better off buying from B&H and selling the lens.

[UnknownVT]

The K-x I found from B&H is $599 with 18-55 lens and before Black Friday. One would be better off buying from B&H and selling the lens.

Yep that seems to be the size of it -
My purchase was exactly that kit with the same thought.
I believe the Newegg price for the same kit is $609 -
and if they have it in stock for Black Friday
(they did not have stock when I just checked)
with 10% Bing Cashback makes it an even better deal .....

BTW - B&H has 2-2.5% on Bing Cashback

EDIT to ADD -
I think prices are dropping -
the kit is $595 at BuyDig.com and they have 5.1% Bing Cashback.....

[LeoTaylor]

I looked inside the Remote F InfraRed device and it is a deal breaker. The shutter button seems to be a proximity switch. The board is surface mount single sided and the "switch" is a wiggle on a trace. I suspect the button tunes the "coil" and the circuit detect the change in reactance. Not something I can connect wires to and externally operate the remote.

No wonder companies charge $80 for a computer controlled IR shutter device for those Nikons that lack a jack!

On the bright side the battery is user replaceable in spite of the manual saying you must send the unit to Pentax.

It seems the K-x is almost a good astro camera except for two simple jacks that all the older cameras have. I was looking forward to the video capability and live view. I really shouldn't be spending $600 on another DSLR anyway.

[JackBak]

I looked inside the Remote F InfraRed device and it is a deal breaker. The shutter button seems to be a proximity switch. The board is surface mount single sided and the "switch" is a wiggle on a trace. I suspect the button tunes the "coil" and the circuit detect the change in reactance. Not something I can connect wires to and externally operate the remote.

No wonder companies charge $80 for a computer controlled IR shutter device for those Nikons that lack a jack!

On the bright side the battery is user replaceable in spite of the manual saying you must send the unit to Pentax.

It seems the K-x is almost a good astro camera except for two simple jacks that all the older cameras have. I was looking forward to the video capability and live view. I really shouldn't be spending $600 on another DSLR anyway.

Yeah, I have come close to getting the K-x as well. Seems that sensor is just the ticket for astro work, but no remote shutter jack! Nope, I've too many projects going to add another to cobble some proprietary IR protocol that I would have to reverse engineer. Think I'll wait for this Sony sensor in a more capable camera body.

[JackBak]

Wow, Jack, writing your own guiding software is impressive. Do you have plans to sell it or put it out in shareware? Do you have any samples of your work?

-Andy

Samples of work later, for now here is a shot of my CCDsnap application. It is so specific to my equipment it would not help most folks. It controls my AP1200 mount, my RoboFocus servo motor, the Philips WebCam and I had hopes for controlling the Pentax K10. Since, that would be a rather painful reverse engineering task AND they seem not to be interested in updating their own remote control software I'll pass for the moment.

You can see there is a control window for the AP1200, mostly grayed out because the software couldn't find the mount's signature (it's not turned on). Same for the RoboFocus control window. The webcam was on and I turned on the analysis mode so that the white square was focused on a "star" in my office. The histogram on the left of that box shows it's not very nicely focused The tracking and focus data are below the histogram - this output could be routed to the ST-4 jack in that the way the histogram box works is by doing a centroid calculation and then repositioning itself to follow the "star".

This all runs only on a linux box and is written in C using the Glade interface tool. It is very compute intensive and tends to bog down older CPU's (although I have put a CPU speed sniffer in it to try to disallow too many calc/second.)

Regards

[pti-andy]

I looked inside the Remote F InfraRed device and it is a deal breaker. The shutter button seems to be a proximity switch. The board is surface mount single sided and the "switch" is a wiggle on a trace. I suspect the button tunes the "coil" and the circuit detect the change in reactance. Not something I can connect wires to and externally operate the remote.

No wonder companies charge $80 for a computer controlled IR shutter device for those Nikons that lack a jack!

The button might be a carbon contact type. Those are really common with remotes and it should not be a problem to use a standard open/close switch or opto isolator.

Do you have a link to one of the $80 IR shutter devices? The remotes I'm familar with for Canon and Nikon are made by other companies and they might make a Pentax compatable version.

Samples of work later, for now here is a shot of my CCDsnap application. It is so specific to my equipment it would not help most folks. It controls my AP1200 mount, my RoboFocus servo motor, the Philips WebCam and I had hopes for controlling the Pentax K10. Since, that would be a rather painful reverse engineering task AND they seem not to be interested in updating their own remote control software I'll pass for the moment.

What an impressive setup! I haven't done any programming since the 8-bit CPU days but still do electronic design. It's great to see such dedication to a hobby. Since your a software engineer, any chance of helping hack the K-x to disable the long exposure DFS? Can't wait to see some of your shots.

[LeoTaylor]

Do you have a link to one of the $80 IR shutter devices? The remotes I'm familar with for Canon and Nikon are made by other companies and they might make a Pentax compatable version

I don't think these companies make anything for Pentax but they are a step in the right direction.
-----------------------

Hap Griffin - Scroll to the line, "While all Nikon DSLR's can be controlled for long exposures with this IR controller, the D70 and D50 cameras can ONLY be controlled for long exposures via this controller. "

Hap Griffin Astrocables
-----------------------

Shoestring Astronomy - Scroll to DSUB-IR1 for Nikon ML-L3 Compatibles.

The Shoestring Astronomy Store - Shutter Control Products
-----------------------

I >think< both of these do not modify a Nikon remote, they emulate the protocol and use their own LED emitter.

Some company somewhere may make a Pentax Remote Control F emulator.