M13 - First Light with a SW Equinox 66 APO PRO

[blackparticle]

FLO had this sitting on the shelf waiting to go home with the boss.

I've been looking to go beyond the camera lenses and the MAK 150 proved impossible for DSO's so this little thing seemed perfect.

I went back to M13 as I'd done a night on it with a 200mm camera lens so I could get a comparison.

I ran off a quick 50 frames at ISO1600 / 16secs. This was about a quarter of the frames I'd done with the camera at f/4 so I wasn't sure how much data I'd get.. Turns out just a single sub looked better than my previous stacked attempt!

Focusing is slightly out unfortunately but really impressed with the scope and the results for such a quick test!

[Bizibilder]

Very nice - Is that on the HEQ5? If so, and with good polar alignment you should be able to get one and possibly up to two minute subs!

[ollypenrice]

It'll be a good little scope but I think focus is way out rather than a a bit, quite honestly. But that just means you ain't seen nothin yet, which is good!!

How do you aim to focus? It really is the be all and end all and needs to be bang on.

Olly

[blackparticle]

Olly - That was focusing through the eyepiece on Arcturus and then moving to the area of sky to shoot. The k10D doesn't have Liveview so it was a tricky case of shoot a few.. In / out / close enough ? I'll have to order a focusing mask when I get home. I probably would have ditched more dubious frames from the stack as well had I a few more to play with.

BB - Yeah. I thought I had a good polar alignment with this one. Used my turntable bubble-level to get the mount spot on and used a boat level to set the home position. Checked the transit time etc. A 60 - 120s exposure seemed to be pushing it too much at 400mm though.

I've had a read of a strip down and tune-up guide for the HEQ5. (Astrobaby's?). I think I'll open it up and see what's going on in there. As it was s/h it might just require a clean, tighten and relube?

The HEQ5 also came with 2 basic RA/DEC handsets. The accuracy of the clock/drive electronics is probably going to be variable in these as well I imagine.

I know with turntables, speed/pitch accuracy is down to a few things. PSU / electronics quality, electrical waveform distortion, voltage stability etc. Surely these things apply here?

[ollypenrice]

Right, so for an estimation of focus throught the EP you did well. With a Bahtinov or Y mask you will do a lot better. You'll be amazed by the difference, really.

Olly

[TakMan]

Great start, but would agree with Ollie about the focusing....

can be a real pain - especially when you can't 'see it'!

How about making yourself (or purchasing a made to measure), Bahtinov Mask..?! The Bahtinov Mask

See here: astrojargon - Bahtinov Focusing Mask Generator: Overview

(just mind them fingers!!!)

Even better - get one for your scope ready made from FLO (and this won't go soggy after a few uses!)

First Light Optics - StarSharp Bahtinov Focus Masks

Used in conjunction with this software, you'll be flying....

Bahtinov grabber for any camera Niels Noordhoek’s weblog

Hope that helps...

Damian

[blackparticle]

Cheers Damien,

I've already got a mask for the 130P so it's on the essential purchase list. I maybe should have asked if FLO had one at the time.

Shame I can't use the software you pointed at. On a Mac.

Alan

[Bizibilder]

If you make your own mask use thin plastic sheet (I use an office file from tesco's!) - it will outlast paper and doesn't care if it gets wet!

[TakMan]

Happy Days!

You're on a Mac too

Yep, it looks like a fine piece of software which I can't use either...

But, I presume you use Stark Labs Nebulosity software then..?

So take a look here:

Fine Focus and Bahtinov Masks | Ask Craig | Stark Labs

If not, I use MicroProjects Equinox and Image software, so you could take a look in that direction....? I use the FWHM values (with my mask), then once in good focus switch over to the Robofocus/V-curve routine..... usually though this is just a check as I appear to hit the focus 'sweet spot' most of the time manually with the mask in place!

Regards,

Damian

[blackparticle]

As far as I can work out, the k10D doesn't have any facility to output live data to a computer. I do use Nebulosity but not for capture as it doesn't support the k10D or it's .DNG files either so I have to batch process first in photoshop to get them into .TIFFs.

I did have a go at webcamming the other night with the Mak and Macbook. While all that worked well having the laptop screen visible ruined my night vision so unless I'm at home and can run things from the caravan, I'm trying to do this without the need for a computer in the field.

Masks for the 66 and Mak ordered anyway. £30 well spent.

[blackparticle]

Olly mentioned Y-masks. After a bit of reading it appears that these can be as simple a bodge job as you like so I made a quick one out of a bit of card held on with my hair bungee until the Bahtinov arrives.

Viewing wasn't as good as the other night with a hot evening stirring up the haze so light pollution was much worse. Results were far more crisp though. Cheers Olly.. made me realise I can make those for my tricky camera lenses too.

146 Frames @15s / ISO 1600

[blackparticle]

P.s. I know there is some slewing on the stars. Nebulosity's auto-grade function has been no help so I stacked everything.

I've emailed Craig Stark about adding a new grading routine based on how circular an outline of a chosen star is rather than image sharpness. I think this would be a very useful feature.

[blackparticle]

I had some time to go through the stack and weed out some of the duff ones. Down to 89 images now and better post processing.

[ollypenrice]

There is a PS trick.

Rotate image so that trailing is horizontal or vertical.

Copy Layer.

Blend Mode darken.

Filter, other, offset.

Experimant with an offset on the right axis. Overdo it slightly, apply and then use Edit Fade to ease back the result till the stars are round.

Olly

[blackparticle]

I did think about that and have tried it with other pics. But if a bright star has smeared across pixels then it is effectively burning out any detail behind it.

What I've done instead is started a library for each object associated with the scope that captured it and I'm just keeping the images with little to no smear on them.

Eventually I'll get to a limit with each archive where adding more data doesn't yield any improvement. For 8-bit RGB (which I think most DSLRs capture at?) that's probably going to be around 768 "Grade-A" images.

I'm presuming the camera will die well before any DSO moves enough for this to matter. (Supernovas being the exception?)

[Coco]

Keep going... there better than my early attempts