Can I image much with a DSLR, EQ5 and 130DPS?

[Ships and Stars]

Hi all, looking to possibly delve into the murky world of astrophotography a little bit as I struggle for time to get away to do visual at my dark sky spot with the big scope. At home LP is terrible lately so I've almost given up on that sadly. 

For my potential 'starter' AP setup, I currently have an old motorised EQ5 with plenty of weights and an as-new 130PDS with Bahtinov mask and a Nikon full frame DSLR with the right adapter to mount on the 130PDS. I don't want to invest in field flatteners and filters at the moment until I can see the potential for results under my LP at home. Probably Bortle 5-6. I'm desperately trying to get the businesses next to me to switch of some key lights at night after they close, they don't normally leave them on but last night was awful. I could literally read my star atlas outside. I shade the scope from direct LP as best as I can. 

May I ask:

Would I be able to image much besides lunar with this setup as is? Objects such as Andromeda or say just general widefield shots? I'm not expecting anything mind-blowing, just a reference image of sorts that shows the object.

Should I try some 20-30 sec exposures in RAW at say ISO 800 or 1600 and see if I can avoid star trails? I can also shoot in bulb mode for longer exposures. I regularly shoot ISO3200 at shorter exposures without any problems and have done a fair bit of untracked night shots in bulb mode for aurora, general stars shots etc.

Is the full frame sensor wasted on a 2" focuser, or should I shoot in aps-c crop frame mode? I have a 2" Astronomik OIII that would screw on to the 2" adapter.  I suppose to cut LP, but might make things too dark. 

Any ideas appreciated, I'm on a bit of a spending freeze at the moment!

Clear skies all.

PS - looking at some tutorials, but don't much much time at the moment until everyone's asleep! 😴

 

 

 

Edited October 5, 2019 by Ships and Stars

[happy-kat]

There's a great thread dedicated to using the 130pds full off images taken by other members. Perhaps you'll have to crop the edges if no ff etc but that won't mean you can't still take images.

[Xplode]

It's not like the corners of APS-C sized images will be great either because of no coma corrector, but at least you're taking some images.

I say use full frame mode, you can just crop after anyway.

[Ships and Stars]

Thanks very much, I meant to add I have a ES 2" coma corrector. When I get a chance I'll set up and try some shots to check the mount is tracking ok as well. I guess I can adjust for backlash on these old motors.

[happy-kat]

This is the thread.

link here

[Ships and Stars]

1 hour ago, happy-kat said:

This is the thread.

link here

Got it! That B&W of the Horse Head is amazing, using an Atik, no DSLR, but I love that image.  Thanks very much! I'll have a trawl through this and give it a go when things shape up weather-wise.

[Fraunhoffer]

Hi,
I have a 105mm refractor that I put on an old Exos2 with a skywatcher EQ5 motorset fitted to it and I use an old Sony NEX5 (APSC sized)
Im very happy with getting 45 second exposures through the 600mm focal length scope just using this  motorset unguided with ISO 800 and RAW format.
I use a Bahtinov mask to get a good focus on a bright star near my subject and spend some time balancing the scope well and setting the polar alignment well.
To set the pictures I bought a cheap intervalometer and set it to do 20 pictures of 45 seconds with the camera set to bulb mode with 15s gap to allow the camera to write the file, 5s preview and get ready for the next picture.
I use the preview just to check all is well from time to time - just my looking - don't touch.
At the end of the 20 frames I check the weather and the last frame and can set another sequence off . 

To stack the frames I take the card out the camera and put it in the PC stack directly on the card using DSS  rather than transfer many Gb of data onto the Pc hard drive.
When Im done I just save the stacks (both with adjustment applied and without adjustment applied) - I don't usually save the initial 'lights' due to lack of hard drive space.

 

[Phobos 226]

If you're up for a project, I and many others have done full conversions of EQ5 mounts with precision steppers and pulleys using the excellent OnStep project.

Total costs can be very low for a full conversion of an EQ5 at around £60-100 for the electronics, about £20-30 for the motors and another £20 for belts and pulleys. The only tricky parts are figuring out a mounting system (I used standard Nema 17 metal brackets that I drilled adjustable holes into to allow the belts and pulleys to be tensioned correctly) and potentially a bit of soldering depending on the 'kit' or controller you base the project on. You will also need to add a guide scope and camera if you want to get into guided images, but even without one some people have been able to use the 'Full Dual Axis Compensation' on OnStep with 6-9 star alignment to achieve up to 3min unguided subs on various mounts. I'm not 100% sure on the numbers on an EQ5 though as I have always guided with this setup, but even that can be achieved fairly cheaply with a converted finder and an old webcam or second hand ASI120MC/MM. I use a cheap 50mm guidescope from Svbony I got for about £50 on ebay.

Overall you can end up with a system that can compete an off the shelf mount albeit with a lower weight capacity for photography, but still just about adequate for a 130PDS and DSLR which is exactly what I am using on mine right now. Of course you'll get a fair amount of dropped frames compared to a higher end solution, but as a rough guide my one of my tests was 40x300s exposures on M33 using my old 400D. Currently I'm fine turning my guiding accuracy and getting everything pin sharp, my best results so far have been a total guiding error of 1.1" RMS seen in this quick and dirty process of 17x300s test on M27 from 2019/09/06.

Hope this helps open up another option for you to consider!

Edited October 8, 2019 by Phobos 226