Which DSO to start with?

[mpeniak]

Hi all!

According to MetOffice there should be clear sky in Plymouth this night and I would like to go out after I finish at work at 02:00 in the morning. I have never tried imaging any deep sky objects before and I do not know what would be a good target. I got celestron c8-n with Canon Rebel and I don't even know how many degrees is the field of view with this combination. My favourite is M31 but is not it too big to fit in just one frame please?

Regards

Martin

[Grant]

Martin, I can highly recommend M57 as a good starting point, its quite bright so shows up well in the cameras screen at the back so you can see how your doing before you go back to the computer... its also great to capture some colour

[mpeniak]

Thanks Grant, how big do you think the m57 will appear with my scope and camera. Is it going to be just a tiny ball?

Martin

[Grant]

Hmmm, if I'm right (still learning this stuff myself!) then your telescope is 1000mm focal length, my ed80 is 600mm focal length, therefore because yours is almost double the focal length of mine the image size should be almost double, heres what M57 looks like through my ED80 and Canon 350D:

(click to enlarge)

So in theory, the little blob of M57 should seem almost double that size for you (assuming you used a 350D)...

Hope that helps (please correct me if I'm wrong anybody )

[Trevor]

Martin

Possibly you will get a magnification of around 30x before you add any barlows,I cant remember if you multiply the Canon cameras by 1.4 or 1.6 for the DSLR.

[mpeniak]

Thanks guys, it does make sense now

[mpeniak]

How precisely do I need to polar align? Is it enough if I pointed my scope with high magnification at polaris?

Thanks

[SteveL]

How about a Globular cluster? Bigger, brighter, easier to visually see, can take shorter subs when imaging... just a thought

[zhgutas]

How precisely do I need to polar align? Is it enough if I pointed my scope with high magnification at polaris?

Thanks

I think very precisely I tried imaging with my 500mm scope and Nikon D70s, which gives half of magnification you'll get, and I still struggle a lot with polar alignment , cause even 30s subs give me a bit (a lot more thanm a bit.. ) of verry annoying star trailing :? I wonder if it's possible that my scope and RA axis are nor quite inline :insects1:

Marius

[Cloudwatcher]

Martin

Possibly you will get a magnification of around 30x before you add any barlows,I cant remember if you multiply the Canon cameras by 1.4 or 1.6 for the DSLR.

To find the magnification using the Canon 350d/Rebel at primefocus use........Focal length x 1.6/50 =

A scope with say 1500mm f/length will give...... 1500x1.6/50 = 48 mag.

CW

[mpeniak]

How about a Globular cluster? Bigger, brighter, easier to visually see, can take shorter subs when imaging... just a thought

Yeah, that's good point Steve! I was thinking about M13...

Martin :-D

[SteveL]

I would seriously think about Globs as first target. They are bright, large, easy to find, easy to image

M13 on a C8 SCT (NexStar 8 GPS) @ f/10 + 350D (unmodded), resized for web, BUT NOT CROPPED!

(20 x 20sec subs, f/10, ISO1600)

[SteveL]

How precisely do I need to polar align? Is it enough if I pointed my scope with high magnification at polaris?

Thanks

Try the drift align simulator

[mpeniak]

How precisely do I need to polar align? Is it enough if I pointed my scope with high magnification at polaris?

Thanks

Try the drift align simulator

Hmmm.looks good but I have not got illuminated reticle eyepiece.

Martin :-D

[mpeniak]

Forgot to mention that your M13 image is cracker Steve

Martin :-D

[SteveL]

Thanks... and oddly enough, that was my first attempt at a DSLR DSO

[Kaptain Klevtsov]

Hmmm.looks good but I have not got illuminated reticle eyepiece.

Martin :-D

Yes you have, Toucam and K3CCD tools. Get the Toucam focused, click the crosshairs thing on and you're there.

Kaptain Klevtsov

[zhgutas]

Try the drift align simulator

That looks a bit confusing to me as a noob :insects1: I wish someone would show me that in practice 8)

[themos]

Before you do the drift alignment, try the quick and dirty Kochab-clock method. Set the scope to 90 declination, put a low-power eyepiece in and move in altitude and azimuth until Polaris is centered. Figure out how big your field-of-view is (mine is 1 degree and 9 arcminutes), figure out in the direction that Kochab (bright star in Ursa Minor) lies in and move alt/az adjustments so that the scope is pointing 3/4 of a degree away from Polaris in the direction of Kochab.

[mpeniak]

Before you do the drift alignment, try the quick and dirty Kochab-clock method. Set the scope to 90 declination, put a low-power eyepiece in and move in altitude and azimuth until Polaris is centered. Figure out how big your field-of-view is (mine is 1 degree and 9 arcminutes), figure out in the direction that Kochab (bright star in Ursa Minor) lies in and move alt/az adjustments so that the scope is pointing 3/4 of a degree away from Polaris in the direction of Kochab.

Thanks themos, I will try that once I got clear sky here. Yesterday it was a pain. I pointed scope towards M13 all clouds came there, so I took DSLR off the scope swung the scope on Mars set the toucam, focused and before I could start capturing frames it clouded over again. I was like this all night, it was the worst night I've had so far I think next time I will only change one object and focus on that one. This is the only thing I managed to image...not particularly difficult I know. (2frames,1600ISO,30sec)

Martin :-D

(click to enlarge)

[Kaptain Klevtsov]

Getting the focus that good is the bit that I find tricky. You have made a significant start with that simple image.

Kaptain Klevtsov

[Vega]

Nice shot Martin ... Is that our Vega ?

[mpeniak]

Nice shot Martin ... Is that our Vega ?

Thanks mate, yep it's Vega like you

Martin :-D