Steve_Field

No doubt Ken, lately it seems like the clear nights are few and far between and with Christmas parties and family stuff I've found that I've had to do a lot more planning to get set up.... Wife made me play dominoes with the kids on Wednesday night and completely blew up the entire evening for me! Now it looks like it'll be overcast down here until next week some time grrrr.... so much I'm dying to try out next time.... prbably need a checklist now! So I've not touched the focuser on my scope since I took the M42 photos... I suppose I could take some flat frames with it. The only reason I hadn't was that I thought the telescope needed to be at the same temperature as it was when I was imaging.

I figured more frames to stack was the ticket. I just started fooling with DSS which beats trying to stack in PS. Curious about dark, flat and bias frames will those help as well? You know the Pentax was also a hand-me-down that was just sitting in a closet and it may very well have a bulb setting but it's probably buried in one of the many obscure menus on this camera. It's OK for a free camera but i'm going broke keeping it in batteries ... i only get about 15 to 20 frames at 30 seconds before I get a battery depleted message and the camera shuts down. I was going to get an AC adapter for it before the offer of the Nikon came along.

Also, the old Pentax K100D only allows for 30 second exposures and really lacks in features. I've got a wealthy friend who has a camera addiction problem that just gave me his old Nikon D80 ... still an older camera and not a Canon but I think it'll work a bit better than my 10 year old Pentax. I'm really curious how you modified your focuser... any details you can give me?

Hey Nigel, Thanks! Actually this was taken without a barlow lens (I moved the primary so that I could remove the barlow fro the optics train). I have a Celestron Nexstar 130 SLT which tracks pretty well when I take my time and get it properly aligned. I love the telescope for it's ease of set up and precise go to puts the faint fuzzies dead center of a 9mm EP but to be honest the focuser leaves a lot to be desired... it's incredibly cheaply made and requires a very heavy touch making minute adjustments really difficult. I added an Orion Accufocus which helps but I've been seriously considering dropping some cash on an after market focuser

OK so I saw this thread recently and it inspired me to start trying to image DSOs with my old Pentax K100D and Celestron Nexstar 130 SLT. I've gotten a few images of M42 amnd M31 but the stacked images have not been all that impressive. I had to use a barlow lens to get my dslr into focus and I kept thinking that perhaps with the focuser racked in so far and with a barlow lens in the optics train that i was not getting as much light to the senor as I could so i set about to try and remove the Barlow lens from the equation. I built some extensions for the collimation screws and locks screw by fabricating bolt couplers out of 3/8 IN rolled steel and tapping them with 5mm x .8mm threads... that size not being readily available around me. The whole modification cost be about $15 US and moves the primary mirror about 250mm closer to the secondary which lets me focus my DSLR without needing a barlow lens AND I still have enough backward travel in the focuser to use an EP if I want... the mod is easily removed or added and could be done in the field if necessary which was my primary design consideration. I don't know if anyone is interested in the details of this mod but let me know and I'll post a detailed thread with pictures in the DIY section. I did a quick test from my driveway on Wednesday night using a stack of 9 images with a 30 second exposure (no darks, flats or bias frames due to having limited time). I keep reading that 20 seconds is the max exposure you should be able to take on an ALT AZ mount but I got 9 good frames out of the 11 at 30 seconds so I'm convinced that 30 seconds is OK and I could maybe push that a little more (and believe me I'll be figuring out where the upper limit is over the next few months). Anyway, this is my 3rd DSO imaging attempt and while it's not great, it did make my jaw drop and I'm pretty happy with it. Next go round I'll see what I can get with the same camera settings and maybe 50 or 60 frames plus darks, flats and bias frames to see if I can get a better image. I also want to have a go at M31 at some point over the next few weeks. Anyway, I thought I was limited to lunar and planetary imaging with my set up but this thread has shown me that quite a lot is possible with an ALT AZ mount...

Here's my first DSO M42 Orion Nebula http://astrob.in/276679/0/ This was a stack of 6 30sec exposures stacked with DSS and then processed in Photoshop to stretch the histogram... still need to work at it as you can see. Going to retry tonight using the Bahtinov Focus mask I built (for better focus) and a stack of at least 40 shorter exposures along with a bunch of dark and bias frames....we'll see what happens