[WerTicus]

wow this is a great result. I cant wait to see what it looks like on a good night when you go out into some country area with less or no light pollution.

[knoxploration]

Yes, there is no power jack on the K-x but I find it is not as needed as it is on the K200D. With eneloops I recently got hours of combined exposure time and still had battery life in the green. It looks like the movie and live view drains it much faster than just plain exposure time.

Makes sense, live view and movie modes both have to run not only the image sensor, but also the CPU and LCD displays continually during the exposure. For a non-live view still image, there's no need for LCD, and the CPU is only needed to do the dark frame subtraction and process the image at the end of the exposure.

Your images are stunning, by the way!

[JackBak]

Thanks for the kind remarks. The Pleiades was not very high in thy sky and was very washed out so I'm really looking forward to redoing it with better conditions. Even so, I'm surprised that so much of the reflection nebula pulled through the murk.

This shot is just 30 - 30s exposures for a total of 15 minutes of exposure time. There was no NR on the camera and I just stacked the jpegs and applied curves. I've never gotten results like this with such sky conditions and lack of processing attention.

Andy, what ISO did you shoot with? I've always kept it between 100 and 400 on my K10 as I wanted to limit any amp noise. Speaking of which can you show us the amp noise inherent in the K-x?

I'm chuckling about the eyes watering. You must be a true night owl or you wouldn't have such sympathy. But yes, you're right... after a while I was seeing spots or rather red crosshairs.

Ah yes the days of the Lumicon hypering chamber, nitrogen gas piped into the back of my LX camera, hand guiding for hours in the cold only to discover you didn't quite nail the focus. Or saying to yourself, Gee I'd love to shoot the Bubble Nebula it's high in the North should be a snap. Then after setting it all up, dialing in the Dec and RA on your mount's verniers you then discovering you can't see the bloody thing. No problem, you say to your self take the damn shot and pull it out of the negative's murk. Doing all that then discovering you only caught the edge of the Bubble in the far corner of your shots. Yes, fun times indeed.

Oh yeah one other question and maybe I've read this already but just forgot. Why did you shoot JPEG instead of RAW. If I'm going to go to all the trouble of astrophotography I always want as much data as I can capture.

Anyway you nailed those two, want to try the Bubble?

Best regards,

[pti-andy]

Andy, what ISO did you shoot with? I've always kept it between 100 and 400 on my K10 as I wanted to limit any amp noise. Speaking of which can you show us the amp noise inherent in the K-x?

The Pleiades was shot at ISO 1600. This seems to be optimal for the conditions at F4. With a little darker sky 3200 might be good also. I'll post some dark frames later to compare the different ISO's.

Ah yes the days of the Lumicon hypering chamber, nitrogen gas piped into the back of my LX camera, hand guiding for hours in the cold only to discover you didn't quite nail the focus. Or saying to yourself, Gee I'd love to shoot the Bubble Nebula it's high in the North should be a snap. Then after setting it all up, dialing in the Dec and RA on your mount's verniers you then discovering you can't see the bloody thing. No problem, you say to your self take the damn shot and pull it out of the negative's murk. Doing all that then discovering you only caught the edge of the Bubble in the far corner of your shots. Yes, fun times indeed.

Wow, you are a die hard astro guy. My film work fell just short of hypering. I was ready to go that route but just didn't have the time to add yet one more process to a hobby that was already over budjet.

I can sympathise with everything you are saying. I think any of us that have spent hours under the dark sky have felt the agoney of seeing a simple mistake after getting the film developed that have ruined hours of expousre time.

I once took a trip out to Arizona and spent 3 days camping in the desert braving the dry dust and heat just to get some dark night sky. After I got back to St. Louis and picked up my 6x7 film I saw that the lab had cut most of the roll through the pictures. I was furious and asked how they could be so careless. The lady said there was nothing on the negs so they just hacked them up and said I left the lens cap on. After explaining everything I went through to get these shots they said they'd give me a credit for my next film processing but couldn't refund my money. Needless to say I "lost it" but didn't help any though.

Oh yeah one other question and maybe I've read this already but just forgot. Why did you shoot JPEG instead of RAW. If I'm going to go to all the trouble of astrophotography I always want as much data as I can capture.

Anyway you nailed those two, want to try the Bubble?

Best regards,

I shoot everything in RAW+ but didn't processes these with the RAWs because I didn't have the time to convert and Registax is extremely slow with TIFF files. If these were taken under better conditions I may have taken the extra effort.

I have found that there really is not much of a perceptable difference between RAW and JPEG anyway when stacking a lot of photos because there is so little data in each frame and the noise and light pollution is so dominate that JPEG artifact is very low on the list.

I've never tried the Bubble Nebula but I do like a challenge. Heck, I don't even know where it is. I hope there are some brighter stars around it to help find and register it. I don't have this fancy "goto" stuff so I have to do everything the hard way. Not sure the sky conditions here would reveal it anyway. Judging on what you are seeing in the Pleiades photo do you think it would pull through?

-Andy

[jbinpg]

The Pleiades was ISO1600???? OMG! What a fantastic result. What ISO did you shoot M31? So the bottom line question: is it the sensor that makes the difference or the stacking method?

[JackBak]

I've never tried the Bubble Nebula but I do like a challenge. Heck, I don't even know where it is. I hope there are some brighter stars around it to help find and register it. I don't have this fancy "goto" stuff so I have to do everything the hard way. Not sure the sky conditions here would reveal it anyway. Judging on what you are seeing in the Pleiades photo do you think it would pull through?

-Andy

Yes, when I saw your Pleiades shot I was thinking of all the shots you could accomplish. Try the "Running Man" Nebula over by Orion, another nice reflection nebula. Try the "Witchhead".

I think with your 400mm telephoto you will have plenty of field to catch the Bubble if you are properly aligned and you just use your RA and Dec collars (verniers) on your mount - I can see that it is one of the Celestron Equitorials.

Good hunting.

[JackBak]

The Pleiades was ISO1600???? OMG! What a fantastic result. What ISO did you shoot M31? So the bottom line question: is it the sensor that makes the difference or the stacking method?

From the less than exciting work I have done with the K10 (CCD) sensor but the same type of stacking process that Andy does I would guess this is ALL due to that Sony sensor - a CMOS sensor at that! Wish I had the budget for the K-x body, alas not right now.

[JackBak]

@pti-andy: I forgot to ask Andy, have you done any prime focus work with the K-x on your scope?

[nightfly]

pti-andy,

Very encouraging results, thanks for posting. The blue response if fantastic, I will be interested in the red response of emission nebulae. The North America nebula is still high, or how about IC1396?

Thanks again for doing some leg work with this camera, looks like Pentax has a usable digital for this field and at a great price.

[Rondec]

Those are amazing shots! I am very impressed with what you were able to do with the kx.

[LeoTaylor]

I'm very impressed with pti-andy's images. The new camera indeed does look good though the old lens may have something to do with it too. And his skill at imaging and guiding.

It has been a long time since I've guided manually. In my K1000 days I used to call it the, "World's most boring video game!" Keep the white dot in the red square for 10 minutes at a stretch. I auto guided with an SBIG ST-7E for 7 years and will never go back to manual. That astro camera could do 15 minute exposures from my MAG 3 back yard. No Milky Way in my city. With the DSLR I gave up on guiding altogether, the exposures are too short to need it even at 2000mm. My LX200 Classic is pretty well aligned using PEMPro 2.

Here is an unguided Meade 2000mm f10 image of a Galaxy Cluster with reasonably round stars:

http://astrophotoleo.com/galaxy/n7619.jpg

Below is my best M31 so far. It is with a filterless K110D but I was able color correct the stars to be white. Stellarvue 480mm f 6, ASA 800, RAW, Internal NR, 10 flat frames, 1 minute * 126 frames (Yes, 4+ hours unguided). I use Images Plus for all processing and it handles the slow polar alignment drift.

[pti-andy]

Thanks everyone for the remarks and input. I had no idea there were so many astro guys on this forum. The user base here is enormous. If we all didn't live so far away from each other we could have a star party!

LeoTaylor, great job on the galaxies. Andromeda looks much like my previous results with my K100DS.

The Pleiades was ISO1600???? OMG! What a fantastic result. What ISO did you shoot M31? So the bottom line question: is it the sensor that makes the difference or the stacking method?

It is actually both. The sensor has improved noise by just over two stops but if you don't stack a ton of photos you won't get the detail. I'll post some amplified dark frames to show just how great the new sensor is.

M31 was a combination of ISO1600 and ISO3200 stacks for a total of 55 frames. In my original photo post I said it was 800 but I forgot that I didn't include those in the stack list because they really were too dark and didn't add anything.

I think with your 400mm telephoto you will have plenty of field to catch the Bubble if you are properly aligned and you just use your RA and Dec collars (verniers) on your mount - I can see that it is one of the Celestron Equitorials.

Good deal, the Bubble is on my list of targets. I just wish we had better weather here in STL. It is rare to get a clear weekend without overcast and moon.

Actually the mount is a Losmandy G8. I wish I had the G11, it is much smoother and doesn't require so many guide corrections. With the small gears on the G8 it sounds like I'm playing a video game with all of my button presses doing guide corrections.

@pti-andy: I forgot to ask Andy, have you done any prime focus work with the K-x on your scope?

Not yet. I just got the K-x and these two were my first photos with it. I will be doing some work with the Celestron 9.25 Schmidt if I can get the mount to behave.

[pti-andy]

Ok, here are the dark frames from the K-x and just to compare the new sensor with the previous 10MP cameras I've added K200D frames. The results are quite astounding!

These are raw frames cropped and layed out in PS. The histogram was clipped on the high end by 75% (64 instead of 255) to bring out the noise. This was done on the final after tiling so that they would all be processed exactly the same.

It is clear that there is at least a 2 stop improvement over the previous generation sensor. The K-x ISO3200 is still a shave better than the K200D ISO800. There is also not nearly the hot pixel problem that existed in the CCD pentax cameras.

I'm so impressed with what Pentax has done here. I just wish I could turn off DFS. This camera is capable of 1-4 minute exposures without hot pixels taking over the shot. Please Pentax, uncripple this camera!

[Gregor]

Holy smokes? Cool pictures. Could someone explain to a newb what the following statement means. I'm assuming it has something to do with accounting for the earths rotation. How is it done?

"All photos were manually guided with a seperate guide scope so the stacks would be as accurate as possible."

Thanks

[Raybo]

Holy smokes? Cool pictures. Could someone explain to a newb what the following statement means. I'm assuming it has something to do with accounting for the earths rotation. How is it done?

"All photos were manually guided with a seperate guide scope so the stacks would be as accurate as possible."

Thanks

As a fellow Newb it kinda goes like this........... you are right-on with you assumption about the Earths rotation.

The longer the focal length the more accurate you need to be with tracking, you can still get some very VERY nice images with a short fast lens and dark skies and short exposers, but darkness rules!


I'm done!

Ray