A thread to talk about what your current astrophoto target may be.

With discussion of the challenges there may be an opportunity to learn and share solutions.

My current project is to better learn PEC and Maxim settings to get good tracking on my mount. I want to be able to have tracking under 2 arc seconds for 10 minute exposures.

I'm practicing to get this system well-tuned prior to going to a 5 day star party at the end of July. Because I'll be under the darkest skies I've been through in a long time, I want to get some wide-field areas.

Specific target for that session will likely be NGC 7000 (North America/Pelican Nebula region).

In the meantime, I'm doing practice runs on M57 to help me show errors in guiding under high magnification.

What's everyone else doing?

I do have sort out how to get rid of noise in the images I took of Cmt McNaught in 2007 but other than that, I am concentrating my efforts in refurbishing a 14.3" Newtonian. Actually it is a complete rebuild to the point where I have test the mirror, and maybe regrind and polish it,before sending it off to be aluminized. When up and running, I would like to have a stab at 1) planet videos and 2) some deep sky imaging. Methinks I will have to replace my current camera first.

Regarding planet videos, I did that many years ago with a Toucam (which I still have). It worked very well once I did the raw/unsharp firmware modification. I think the big discussion now is that only some DSLR models are doing 1:1 pixel videos - most are doing some sort of binning which would blur planet details.

I'm going to pick up the new Orion 3MP autoguider/planetary camera in the coming weeks and try that out on the moon eventually. Maybe the sun, but the problem that I found with the transit and eclipse was that it's really hard to see a laptop screen outside!

FWIW, my efforts last night with m57 were an exercise in what goes wrong when you add a heavy camera accessory to unbalance a system. I didn't think that it would make that much of a difference, but it really did. I'd balanced the system without the cooler in place and it was alright, but didn't plan for what the extra weight would do.

I do also have a couple of lightweight equatorial mounts. I am thinking of ditching a 6" Newtonian scope and just use the mount as a camera platform. I need to figure out how to mount a stepper motor on the RA axis. I do have a Pentax 645 with 45mm and 150 mm lens, several PK mount film bodies and my trusty old *ist DS. I'm sure my wife will want me to sling her Nikon D200 on there somewhere. Tail of Scorpius almost reaches the zenith so might be a good place to start. Also some nice galaxies in Grus may get targeted.

One challenge with shooting film is focus. You could focus a lens on a digital body, secure the position with tape, then mount it on the film body. Might work well enough for playing around. Would be difficult with medium format I think.

I'm very new to this medium, first I'd love to catch the milky way. Then on to more difficult targets. Here are my first night sky photos:

460545_10150915927202390_566417389_9806823_1551416549_o | Flickr - Photo Sharing!

460026_10150915927312390_2071380834_o | Flickr - Photo Sharing!

464081_10150915927127390_1071661411_o | Flickr - Photo Sharing!

I know there is a huge difference in night sky and astro-photography, but you have no idea how happy I was to get this half right.

Nice start with star trails. Did you use stacking software to help or are you using single long exposures? I think it's stacking software because some of the trails appear spotty - but that could be because of clouds.

I've not done star trails - too many light domes to the north to make it worthwhile. That may change when I go to a dark sky site later in July.

Not much "serious" for me to do during the current times of white nights that we suffer from in Scandinavia until August. (Well, young couples may have a different opinion about Scandinavian summer and white nights),

However, I will use my vacation to take my newly acquired O-GPS1 though its paces and find out how it will work at different Alt-Az directions and at different focal lengths.



Very first light (in horrible weather) for my new O-GPS-1: Star Arcturus with a K-5 and
an smc Pentax-M 100mm f/2.8 lens and a 30s exposure with and without Astrotracer function.
Images were taken a couple of days apart and the latter at an earlier time of the night.

B.R. / Steen G. B.

Hi smigol,
Yes it was partly cloudy that night, I used a shutter release cable and a 7-13 minute exposure. Then I messed them up some in Photoshop! I'm planning to give up food so I can afford a better telescope! Great job Stone G.!

This past week I've been out in the backyard working on getting my settings right for my mount and trying a high magnification target.

My success was pretty decent given the challenges that I ran into.

First, I did a full re-train of PEC on the mount -- alas, it also appears that I programed the curve in reverse so that the mount was fighting itself. I've fixed this but it was annoying to realize afterwards.

Second, I found that the DEC backlash in my mount will become problematic for doing precise pointing with the goto setup, especially for high magnification work. Pointing accuracy was off by a half a degree. This doesn't seem like much but it makes a difference. I've got some belleville washers on order that I'll use to see if it can take up some backlash on the worm.

Third, because of the backlash on DEC, working with an imbalance in that axis is critical. Because of the scope setup, I'm going to look into getting an imbalance on DEC that persists through pointing at zenith. Maybe another string and weight concept might work or attaching an outrigger for the weight.

Fourth, when leaving the tripod set up for days/nights at a stretch, it's important to recheck polar alignment to ensure that settling hasn't effected things.

Here's a few pictures of the setup and of the results:

Setup:


Orion Maksutov Cassegrain (1540mm fl at F12.1) guided by Orion ST80 (400mm at F5). Gives a scale of .74 arcsecs/pixel on the K10D. Guided at a scale of 2.6 arcsecs/pixel.

Results:


29 lights of 10 minutes at 400 ISO with a cooled K10D. CCD Temps were between 13-17 C. Stacked with DSS 3.3.3 beta 47. Processed in PI. Because of stacking in "intersection mode" the frame is a little different than the full size. Also, much of the amp glow is removed from the edges.

Cooled K10D:


Pretty ugly, but gets the job done.

Hi Steve,
Did you do the cooling mod yourself? Nice setup.

The mod is pre-fab parts:
Peltier device: Tellurex PK-1
Controller with temp probe: Oven Industries 5R7-350A
Gel thermal pad from Digikey
Powerwerx for the Powerpole to F connector.

I replaced the 80mm fan on the heatsink with a Pabst model that I had to have a slower spinning model with less vibration.
I did also add a bit of aluminum sheet below the camera body to help pull heat away there as well.


When the cooler runs at full power for a while, ice will form along the exposed edge of the gel pad. Because the K10D is mostly weather sealed, I'm not worried about water intrusion. There can be a little condensation that appears on the inside of the LCD panel. It usually evaporates completely once the camera warms up.

The background is much smoother and I get very usable images at 400 ISO. I don't wish to push it higher at this time.

So the cam is externally cooled rather than a stripdown and a cold finger inserted behind the CCD?

Yes, it's externally cooled. When I had the camera converted at Spencer's, I opted for their temperature modification as well. On reading what they do with this mod, it appears that they install some thermal transfer material (maybe a gel pad?) to help move heat from parts to the metal frame of the body. Comparing it to my stock cameras, I can feel the LCD panel and the base of the camera become warm to the touch during long exposures. This is even with the LCD off all the time. Thus, by cooling the warm areas, I'm able to help the camera shed heat.

I've tested putting the K10D into the freezer to see if it will give better results and even remove the amp glow. It seems that there will always be a glow on the edges, even at -10C. I just frame my targets to avoid that part of the screen.

Here's what a dark from an unmodified camera looks like at 21C:



Here's what a dark from the modified and passively cooled camera looks like at 21C:



And here's what a dark from the modified and actively cooled camera looks like at 21C: