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Help on this Tiny Object NGC 925

Posted: Sat Feb 07, 2015 11:10 pm
by astronomynut
I accumulated this data on the 5th of February. I used my Explore Scientific ES102ED atop a Celestron CGEM DX. I used BYEOS to control my Canon 600D (unmodified). Guiding was with a 50mm Guide Scope using an Orion SSAG controlled by PHD2.

Data consists of twenty one 300 second exposures at ISO 800, with matching flats, darks and bias of 20 each.

I get the feeling that my problem with processing this is either that my data is bad, of the object is just too small for my imaging system. I was unable to get much of anything out of this data. The results of my struggles are located here http://www.astrobin.com/154445/

I have up loaded a version at https://drive.google.com/file/d/0B6hwUm ... sp=sharing

The data is without any change with the exception that I binned it to the usual 50 percent and cropped it considerably.

Maybe someone who has time can tell me if my data is bad, or maybe if it is ok, you can point to how to develop what I have as much as possible. I keep seeing one person up on Astrobin with seems to get absolutely wonderful photos out of just two or three lights, and just cannot figure out how he accomplishes it. I have to guess he is taking these photos at a totally dark site, unlike my Bortle 4.5 light pollution site.

Maybe someone could suggest how I can get rid of some of this light pollution, so that it doesn't make it to my camera sensor. I know I get a lot of noise from this light pollution, but then again, I keep seeing results of others who live in metropolitan areas that have really bad light pollution. I am guessing that they compensate with the use of a Mono CCD camera. I was thinking of purchasing a OSC CCD Camera to deal with my sensor heat noise due to the fact I live in the high desert of southern California, and the heat I have to put up with. Any suggestions on one that would do nice work, without breaking the bank (less than $2000US). And, if I purchased this camera, can I process the data with Star Tools?

I guess that's all my questions for now. I hope someone can tell me it I am wasting my time on these small galaxies, or if I just, still haven't figured out how Star Tools works. I certainly tried just about every slider and button in the menu, and work this data at least 10 times, with the results as you can see, very poor. Caley

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 12:09 am
by Cheman
Hi Caley
To me, that is a small object to be imaging at your scale. Not that it cant be done, it can. Just as a comparison here is a NGC 925 that I took with my Meade 12" acf. My exposures were 45 at 1000seconds each. Granted, you cannot compare apples to apples here re: scopes, cameras etc. But with the increased light gathering capabilities of my larger scope, I still used much longer exposures than you and more of them as well. I would try longer exposures and more of em. Maybe Ivo or others will have more suggestions for you.
Image

Che

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 12:21 am
by astronomynut
Che, I thought this was somewhat of a faint and difficult object. I guess I should be happy with what I managed. You can just discern two of the arms and of course, the core.

I do have a larger telescope, a TP 8" RC, but I have been having some difficulty getting things set up properly. I'm almost there, but still need to tweak the balance, and get used to the focusing. I am spoiled by how easy it is to focus a refractor. I take about three times as long to get the RC in focus.

I've already decided that my limit on smallest size for my 4" refractor is about 20 arc minutes in size. I spent time downloading a list from "Deep Sky Objects Browser" for tomorrow nights photo outing. I will have to choose one positioned properly, and of a fairly good magnitude. Hopefully I will get something that looks like more than a haze amongst a star field. Caley

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 12:28 am
by Cheman
Caley
focusing is certainly an important factor. I usually recheck focus every two degrees F temp change. Some nites, that can be a lot of focusing ;)

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 3:25 pm
by astronomynut
Che, I usually do focusing once. Guess I should try doing it more often. The problem is I am not automated when it comes to acquiring an object. I use Precise GOTO of the mount. I've found I just cannot quit on an object, slew to a bright star to focus, and then get back to the same position on the object I was photographing, but I guess I will need to get used to losing 10 percent or so of my photos. Just difficult when you are on a large subject.

Your photo on Astrobin was the one I was the one I was using, in the hope of extracting some detail in my. I use other peoples photos as guides, and yours is a very nice example to use. Caley

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 4:26 pm
by Cheman
Hi Caley
what is your method of focusing? Visual? software? Focusing mask? I use Nebulosity for capturing my images. I frame my image, then use its fine focusing module, selecting a star in my field of view. Then i start capturing frames. When I want to refocus, I stop capturing, start the fine focus module again, and pick the same star I used before, no need to move the mount or reframe. Does BEYOS have a focusing routine? If you are visually focusing on the screen of a DSLR I could see where it would be difficult.
Che

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 4:35 pm
by Cheman
Another thought. If you must move your mount to refocus, look into a program called Astrotortilla. It will plate solve an image you've previously taken, and move your mount to that object, take an image and plate solve it, move it some more, and repeat until your mount is centered on the coordinates of the first image.
Its a free program, but can be a bit of a pain to set up the first time.
Che

Re: Help on this Tiny Object NGC 925

Posted: Sun Feb 08, 2015 8:14 pm
by astronomynut
I try to use a focusing mask, but am not always that good with one, so I end up using Live View on my DSLR via BTEOS to refine things, using the digital readout to get the lowest number.

Most of the time, I do have to move to a brighter star, because there aren't any bright ones in the FOV of my DSLR that I can see the diffraction spikes of a mask. Never thought about just keeping the mount at the imaging location and trying to see if BYEOS can pin down the focus on those very faint stars. Guess I can try that tonight, weather permitting. There should be plenty of stars in the FOV because I will just be working on a star cluster or two.

I've tried to automate my pseudo observatory, but I cannot get anything working through ASCOM or Stellarium Scope. Seems my Norton AV doesn't like one of these programs, and has kept deleting part of the program it sees as a threat. I'm seriously thinking of trying SkyX, which I hope will not have that kind of problem of the cobbled system I was trying to put together.

Right now I have my cables running to my desktop computer out next to the mount, instead of having my computer inside my house, so I go outside every 20 or so minutes to check to make sure the mount isn't hiccupping, or that the focus has gotten really out of whack.. Caley