Thought I'd share this pic from last night. I'm not stacking or processing images yet, but happy to have the camera grabbing an image through the tube!
I think today is my one week anniversary with my telescope and when i think of it that way, I'm quite happy with the progress I've made, thanks in large part to members here.
This is a single exposure (sub?) at iso 1600 for 30sec on a canon eos550d, through a skywatcher 200pds on a heq5pro.
Are there any tips on focussing on faint objects that don't register on liveview on the camera? I had a few goes at omega centuri last might, the only way i got close to focus was to slew to alpha cent, focus on that, then slew back. Is it generally easier if you're previewing on a computer screen?
Anyway, here is the pic! I've a long way to go and wouldbe keen to hear feedback!
What you did by focusing on a bright star first then slewing to your DSO is the right way to do it. All objects out there be they planets ( close ) or galaxies millions of light years away have the same focus point ( infinite focus ). So you’re on the right track. Are you using a bahtinov mask when you focus on the star ? That will give you correct focus for your sensor not your eyes as everyone’s eyes are slightly different.
As far as aligning objects in your frame without being able to “ see them “ in live view, the best way I’ve found is to look for a recoginisable pattern in the stars and align that where you want it in your frame. Then take a quick shot. You can crank the iso up for this shot because it’s a test and it’s quality doesn’t matter that much as long as you can see the object. That way your test image doesn’t need to be very long. Once you have it framed where you want it, then take the iso back down to a good noise vs signal iso. This maybe 800 or 1600 depending on your camera. People will chime in here and tell you what “ sweet spot “ your camera is. This can be used as a starting point.
What you did by focusing on a bright star first then slewing to your DSO is the right way to do it. All objects out there be they planets ( close ) or galaxies millions of light years away have the same focus point ( infinite focus ). So you’re on the right track. Are you using a bahtinov mask when you focus on the star ? That will give you correct focus for your sensor not your eyes as everyone’s eyes are slightly different.
As far as aligning objects in your frame without being able to “ see them “ in live view, the best way I’ve found is to look for a recoginisable pattern in the stars and align that where you want it in your frame. Then take a quick shot. You can crank the iso up for this shot because it’s a test and it’s quality doesn’t matter that much as long as you can see the object. That way your test image doesn’t need to be very long. Once you have it framed where you want it, then take the iso back down to a good noise vs signal iso. This maybe 800 or 1600 depending on your camera. People will chime in here and tell you what “ sweet spot “ your camera is. This can be used as a starting point.
Hope this helps
Cheers
Ryan
Thanks, Ryan, sounds like solid advice mate
I don't have a bahtinov mask yet, though i did download a template for one this arvo, will get onto it.
Also, good tip on locating stuff in a frame with that high iso test shot, will do that in future.
Cheers!
I use the framing assistant in N.I.N.A (software similar to APT). If you enable the rotator in the equipment tab and just set it as 'manual' it will slew, solve the image then tell you which way to rotate the camera manually. Then it repeats that process until your target is framed. It's quite accurate and the built in skyatlas is ok (not as good as a standalone program like stellarium).
I also try to use a bright star as close as possible to the target for focusing, I've found focus shifts a little if you slew too far from where you focused, but that could just be my setup.
NINA is pretty new, and takes a bit of getting used to. I lost a few clear nights when i first started using it due to various misunderstandings on my part. There are probably other options out there that can help with framing.
JP
I focus semi automatically using my JMI moto electric focuser attached to my focuser and use my eyes as a final litmus test
Previous to that I used the FWHM focus feature on BYEOS but found it was hit and miss with sharp focus
On BYEOS live view frame and focus , I find a magnitude 1.50 to 2.50 star not far from intended object and take a series of 30 sec exposures , tweaking in and out until the diffraction spikes are sharp as possible ( atmospheric conditions do affect your star diffraction spike sharpness )
It’s a painfully long process ( 15mins ) but usually get tac sharp stars 90% of the time
Be advised that your focus on an object can drift over 2 or more hours as your object ascends. It’s happened to me on a few occasions. If your imaging for only short periods I wouldn’t bother checking each frame , just the first few
Cheers
The focus in your image is not too far off , Eta Carina Star is not too far off sharp focus , although you have slightly eggy stars at 30 sec subs possibly due to polar alignment and tracking
A couple of weeks worth of progress on this target and surrounds.
Bahtinov mask is on and getting it done
More than one shot . This is 57mins worth of 20sec at 1600 iso (with an f5 8" newt, heq5pro and stock 550D)
I'm getting there slowly with processing, but will spend some time tonight learning masking. I think there is more here but the keyhole is already a bit blown out, as is eta carina.
Anyway i might make this a yardstick of sorts, come back to it to guage progress.
Hi team,
New scope arrived today and was surprised by a few hours of clear skies to play with it tonight. The scope is a william optics zenithstar81, with the 6aii flat.
Here's a go on Carina in narrowband, 32 x 1min O and H, 34 x 1min S.
And a link to astrobin for larger viewing. I shot at 200gain, 50 bias. I need to read about why its good to use lower gain.
Looks like you have accelerated quickly into great imaging.
I did the Craig Starck gain test recommended by Marc. Contrary to a lot of complicated online advice the ASI1600 works better for me on a much lower gain and this is also true of the OSC. Try 75 gain as a maximum or even lower for longer exposure and you might find your Ha images in particular are less blotchy.
Quote:
Originally Posted by jahnpahwa
Hi team,
New scope arrived today and was surprised by a few hours of clear skies to play with it tonight. The scope is a william optics zenithstar81, with the 6aii flat.
Here's a go on Carina in narrowband, 32 x 1min O and H, 34 x 1min S.
And a link to astrobin for larger viewing. I shot at 200gain, 50 bias. I need to read about why its good to use lower gain.
. This is 57mins worth of 20sec at 1600 iso (with an f5 8" newt, heq5pro and stock 550D)
