Video Astronomy Rules

[allan gould]

On Friday Night I used my new 127mm Apo scope with Lumicon focal reducer and Watec 120N+ camera to see if I could image through the light polution of Brisbane. NGC5090 and ngc5128 were both 200x10 sec integrations while M4 and ngc4945 were only 10x10sec integrations. The reasons for the latter two not being so many integrations was that I wanted to preserve the bar of stars across the middle of M4 and when shooting ngc4945 it was almost vetical and the scope was about 2mm from the tripod leg (forgot to put the vixen pier on the mount).
I was pleased would be mildly saying it. Ngc5090 and its three faint companions were mag 13.2 galaxies which I was happy with.
The one shot of ngc5128 has been further stretched to show the "egg shaped nebulosity" rarely shown with this galaxy.
I have to go to a dark site and really test ou this camera but it so easy to use and has great software in comparison to my DSI Pro and SBig is a real doddle. Also very, very pleased with the new 5" apo scope as these shots were taken with no IR filter in place.
Regards
Allan

[Kokatha man]

Very nice shots Allan, those dark skies you're seeking should produce some real blinders.

This was on the HEQ5 Pro? Any auto-guiding? (though with 10 second takes, this really is a dumb question!)

Must check out this Watec 120N+ camera specs for myself on the web.

Congratulations, Darryl.

[allan gould]

No autoguiding. Just polar aligned and started taking photos and yes it was the HEQ5Pro. I tried 30 and 60 sec integrations but the skyglow had me nailed so I settled for 10 second shots.
The Watec 120N+ is so easy to setup, focus and use with virtualdub. The GStar cameras are the same I expect.
I almost forgot: Peter, thanks for the company and Steve for the advice

[renormalised]

Good shots, Allan:)

I'm particularly impressed with your shot of NGC5090 and its companions. You know, if you look carefully, you can see many more galaxies in that shot. I counted at least another 6 that I could positively identify and I will bet that many of the the faint dots in your shot are galaxies too. Some, of course will be dim stars. Looks like you've pushed that shot to about 17mag, by the looks of those really faint dots. You want to try and up the exposure and see if you can bring out those faint fuzzies:)

It'll be better at a darker site, anyway. Go for a drive upto the Glasshouse Mts and try from there.

[peter_4059]

Allan,

They've turned out great. I'm looking forward to seeing NGC4945 from a dark site. Now you can move onto LRGB. Have you ordered that new laptop and filter wheel yet?

http://www.iceinspace.com.au/forum/showthread.php?t=30444

Peter

[allan gould]

Thanks for that peter
Allan

[peter_4059]

No problem. Draw up some pool plans and you'll be able to treat yourself to a laptop as well. ;)

I'm still ironing!

[Phil]

Great stuff Allan Very nice shots
Phil

[peter_4059]

Allan,

Thought you might be interested in how the Watec compared to the DSI II at similar conditions (except for the fact that I had double the aperature on my side).

Here's my M4 through the DSI/10" 7x11 secs taken at the same location at about the same time.

The Watec/5"APO sure is a fine DSO combo.

Peter

[Bassnut]

Peter, mmm, I assume you arnt auto guiding, yes its a sensitive cam, but for 10secs, you got some serious tracking issues there.

[peter_4059]

Yeah you're right - after spending 30 mins drift aligning I needed to rotate the OTA to get to the finder scope and stuffed up the alignment.:doh:

[Prickly]

Hi,

Those are some great images you have there.

I was wondering what these cameras are like with a single integration (eg. 10sec) in suburbia with the 5 inch scope. Can you see more through the eyepiece or on the screen? With the middle shot for example did you see much with a single integration?

I have been considering doing something similar down the track so its great to see the results through a similar sized instrument. I would probably be more interested from a visual perspective (on screen) rather than imaging.

Cheers
David

[allan gould]

What you see on the computer screen with virtualdub is a single integration of 10 sec only. The screen is updated every 10 sec with a new image. So if you stumble into the mount you only lose 1 frame out of all those you have captured. You capture as an avi. Then use avi2bmp to make single frames and stack with deepsky stacker or you can use Registax to stack your frames directly and remove darks.
To show you what you see on the screen from one integration of 10 seconds see the attached photo. The gain has been ramped up but its exactly what is on the screen. You can see far more on the screen than thru the eyepiece. Ngc5128 was not visible in the eyepiece due to light pollution from Brisbane. No manipilations have been done to this image at all ie its a raw file.
Also remember that the Watec 120N+ can do UNLIMITED integrations on the fly ie of 1 min or 10 min (but I havnt gone there due to light pollution). But I have done 1 min integrations of a very dark suburban scene that I saw no light at all and it turned it into a daylight shot. The Watec 120N+ can be obtained from Steve Massey and I say up front that I have no connection with him or his business except as a very sattisfied customer and as a recipient of his knowledge.
I also acknowledge that I purchased the 5" StarPro scope and Lumicon focal reducer from him as well.

[Prickly]

Hi Alan,

Thanks for posting the image. Still very good isnt it even at 10sec. I wonder whether light pollution filters might help out too by improving the contrast and enabling longer integrations?

In any case - you seem to have some great results and thanks for showing what they are capable of. Very impressed.

David

[allan gould]

I should add that I have one acquaintance that uses three GStar EX cameras as spotting scopes at low, medium and high magnifications to find objects for his 20" SDK scope. And to do occultations etc.
Now thats giving in to the dark side.

[allan gould]

Crossed threads.
You can ramp down the gain to get a more natural shot but a LPS etc filter would give you a cleaner shot, but of course like all imaging a dark site would be best.
But I was amazed at how it cut thru the pollution to give me images that a DSLR (without filters) goes completely orange in 30 secs at iso800. Cant use a DSLR from my house at all.

[winensky]

Ah the filter question. How do you think it would go with a Ha filter for example on a neb shot from your location? By the way I love the shots and agonized over the RGB vs. Video question at the start of my imaging experience.

Kind regards
Matt

[allan gould]

I may try an LPI filter to see if I can go longer on the integrations. I may try an Ha filter if I can get my hands on one.

[Prickly]

Hi Alan,

I use a UHCS which I quite like. Stars have a tendency to go a slightly bluish green colour but that wouldnt matter with black and white.

If you stack the UHCS filter with a red then you would mainly select the Ha (so Baader say), but probably not as good as a dedicated filter. Looking at the transmission curves for each though I would think it might work pretty well.

Cheers
David