SteveNickolls

I do love these wide field shots, keep them coming!

Here's two taken Sunday night (4th December), first M81 & M82 and friends (only x10 fifty second light frames at ISO 800 plus x50 flat frames and x50 bias frames) taken with my Synscan alt-az mount and Canon 600D DSLR at 200mm FL-

And the face-on galaxy NGC 2403 (again only x10 fifty second light frames at ISO 800 plus x50 flat and x50 bias frames) also 200mm FL-

I have a new lightweight set up for taking these wide field shots making it easier on cold nights with not having to put out the telescope to piggyback the camera on-

I can align the camera with the mount and have been attaching a hand warmer to the end of the lens to keep the dew away (it works).

Here is a wide shot of part of Auriga taken using the camera piggybacked on the telescope and using the Synscan alt-az mount (on the 28th November 2016). The image is from x39 sixty second light frames at ISO 800 plus x60 flat frames and x50 bias frames. There was a great amount of moisture in the air that night and masses of scattered local light pollution. I used a lens at 100mm FL.

Cheers,
Steve

He, he I'll let you off then :-) Nice lens. Sure you will get lots of enjoyment from it.

BTW there were three of them 2nd hand on mbp.com all very good, two were virtually new.

Cheers,
Steve

http://www.365astronomy.com/Blitz-Hotshoe-dSLR-Camera-Adapter-and-Deluxe-Multi-Reticle-Red-Dot-Finder-COMBO.html

I'm almost sure I once had one of the hot shoe adapters but it did not fit well being too loose.

Cheers,
Steve

Hi Ken, I don't know about 'great minds' etc but this may solve your connection issue-http://www.rothervalleyoptics.co.uk/geoptik-slr-hotshoe-synta-finderscope-adaptor.html I have also read you can use parts from curtain fixings to go into the camera hot shoe then connect them to a finder. BTW did you beat me to the Canon 85mm f1.8 lens on mbp.com? :-)

Good luck with your wide field imaging.

Cheers,
Steve

2 hours ago, The Admiral said:

That's where a new forum topic would help!

Well I have posted on the thread asking when Admin are going to do/say anything. And I was polite and everything yet still no reply. Are we being ignored?

I have come across this, it refers to Canon cameras- https://www.dpreview.com/forums/post/34453855, is it a help?

Just a thought, although bad pixels are a fact with sensors I have much more problem with my images being affected by light pollution.

Cheers,
Steve

1 hour ago, alacant said:

Light, flat and bias frames and randomly nudge the mount a little after each exposure maybe too? HTH

The Synscan does the nudging pretty well all by itself, calls it tracking but doesn't know when to stop :-)

Cheers,
Steve

3 hours ago, The Admiral said:

It seems the accepted approach is to use the bias as darks and use a rejection mode (e.g. kappa-sigma clipping) for stacking. A bad pixel map is also referred to. More reading is needed I think.

We already use bias frames and let DSS apply kappa-sigma clipping but a bad pixel map might a learning curve step too far at least for lil' old Luddite me who likes to embrace the KISS principle. I wish you all well of course with this and I will read the thread in case it is something more I can achieve :-)

Best wishes,
Steve

31 minutes ago, The Admiral said:

The 'darks' debate has been around for some time. If you are interested, here's a thread that might set you thinking https://stargazerslounge.com/topic/223975-dslr-imaging-do-you-really-need-dark-frames/?page=1

Ian

For Ken's cooled camera take darks. For the rest of us without that capability use the time to take more light frames instead :-)

Cheers,

Steve

12 hours ago, parallaxerr said:

So, I feel like I have come to these conclusions (until I have another great learning experience):

·         Plan imaging sessions better – one target at a time.

·         Maximum ISO – 800.

·         Read noise for my camera is irrelevant.

·         Semi-apo filter is not required.

·         Don’t waste exposure time on darks.

Hi, we have different DSLR's but through experience I agree with the conclusions you have come to-

• You need to stick to one target per session and get at least an hours worth of light frames, hopefully more to get a decent final image. If you need more frames carry out consecutive night imaging to cut down the effects of field rotation. The exceptions to an hour of images can be clusters and globular clusters.
• Iso 800 is fine to keep your signal more to the left hand side of your histogram for later stretching.
• Due to the different dark noise routines built into DSLR's (and they are probably all commercially secret and different), plus our ability to not be able to control the sensor temperature then dark frames aren't worth taking. 
• I haven't had chance (due to the bad weather here) to use my semi-apo filter but I do hope it has a benefit with the bloated stars etc.

Cheers,
Steve

Good luck imaging tonight if you have clear skies. I wish now I had ignored 'clear Outside' and set up earlier as the current sky is mostly clear here but have made do with my binoculars. I've just come in from the cold and once warmed back up will go outside for a second session.

Yesterday I finished a portable screen to protect from the wind blowing down from the north, it should mean I will get a few more nights of imaging over the course of the year. :-) Here's a posed image from yesterday.

Objects clear the top of the screen at around 28 degrees elevation. Being on top of a ridge means we get strong winds and while the observing spot is well protected from prevailing wind from the SW those from the north hit it full on.

Cheers,
Steve

Excellent Ken, you are revealing the dust from out of the dark-well done.

Cheers,
Steve

Sorry to hear that the weather has been up to its usual tricks in many places. I too had intentions of imaging last night (the first opportunity in around a month) but when I wanted to set everything up in the late afternoon the clouds looked very dark, threatening rain. Later on we did get some clear areas of sky but had I been imaging I would have been concerned at the big clouds moving across the view. In the end I used my trusty 15x70 binoculars to do a couple of observing sessions. There was a lot of turbulence around the waning Moon. At least it was good to get outside. Do hope we all get some clear, dark skies before too long.

Cheers,
Steve

Thanks for the link Ian, I've just begun reading part 1.

Cheers,
Steve

3 hours ago, parallaxerr said:

I've had a look back through the thread for posts about filters and came across two posts of interest.

@SteveNickolls, you mention using the semi-apo, have you tried it yet? I rate the 1.25" one I have highly for visual and am considereing the 2" for AP.

Hi,

The filter is a birthday present and I shouldn't be using it before next week. I will of course let you know how it performs :-)

Cheers,
Steve

1 hour ago, parallaxerr said:

so may invest in a bahtinov mask.

A mask will make focusing that much simpler. Good luck imaging. The equipment looks good :-)

Cheers,
Steve

Taking up Neil's concerns over potentially divisive words like budget, Alt-Az, EQ etc. the common thread running through our imaging is the duration (or lack) of individual frames. Our imaging takes up the central ground between very short exposure EAA and established EQ imaging. EAA had to fight for their recognition just as we are doing. What we are pursuing is the inevitable opportunity presented by growing technology that allows the unthinkable of capturing decent images not thought possible only a few years ago.

I rather think the growth in shorter duration imaging is inevitable given the development of more sensitive CMOS camera chips not needing long exposures and improved mount designs. In the future the use of heavy EQ mounts, while still having a place to allow imaging to the zenith and more accurately track objects, will diminish as more and more people see the advantages of using lightweight portable mounts and greatly more sensitive CMOS cameras. 

However getting back on point the discussion thread can surely accommodate discussion including mount types which by their inherent design share the limitation of imaging duration. Joseph Ashley had to draw some boundaries to sensibly limit the content of his book but we can afford to be a little more generous with no publisher or deadline to meet. More importantly the challenge, drive and ideas that cross platforms should not be lost because the paper was too small. Anyway just my 2d.

Cheers,
Steve

1 minute ago, Nigel G said:

I agree a new thread to discuss this is a good idea.

So, last night I had a battle with my imaging PC, It shut down on its own 3 times while gathering subs, 3 hours spent getting 1 hour of 30s on Horsehead, flame & Orion with my 135mm lens. then the fog rolled in. DSS refused a few subs.

I took darks flats and added the stock bias. I had a very hard time removing gradients so i'm re stacking without the flats to see if that helps.

The info is there, removing the gradients has taken so much detail out though.

Canon 1300D 135mm lens, 94x30s light ISO 1600, 40 flat, 50 dark, 50 bias. Star Discovery Alt-Az mount, DSS & StarTools.

Cheers

Nige.

The diagonal composition is lovely Nige but is this less=more in LIFE to give you the roundalls over the stars?

Cheers,
Steve

55 minutes ago, Stub Mandrel said:

Perhaps as an imager with a light , unguided EQ mount I am in a minority of one?

I think Neil we are each somewhat in a minority compared to mainstream EQ imagers but together as one we have made much more than could have ever been imagined-all the posts and the number of views both show the interest of other members (and browsing from the wider public). There is quite obviously an unfilled demand for help from those interested in imaging and who for different individual reasons don't or can't use the mainstream EQ approach to imaging but are looking nonetheless for help much as we all did and still do.

The progress of technology found in new lightweight mounts, CMOS cameras and processing software all work to make what once was impossible possible. It is a great freeing movement and one full of people with the creativity and desire to experiment. Our new topic is well fit for meeting the future and if you will forgive me an apt quote, "O brave new world, that has such people in't!" :-)

Cheers,
Steve

2 hours ago, Filroden said:

I'd suggest a couple of things:

- create a new thread to discuss this very topic to this thread can stay focused on imaging DSOs with alt-az mounts until a conclusion is reached

- first discuss the objectives and outcomes being sought before reaching to conclusions and solutions

Thanks so much Ken for this way to discuss the way forward, we can create a new thread just to discuss things and move on from there. Looking at the replies Nige got it's not a definite 'No' from Admin so we need to be sure what we want.

We mustn't get bogged down or misled by lines we  might immediately draw in the sand; Joseph Ashley's book had to make some definitions which suited him but aren't necessarily what we desire. If we can get a new topic heading from Admin then divisions such as EQ and Alt-Az, budget, telescope type, cameras, different software and image galley find their own natural place within the greater scheme of things. 

Cheers,
Steve

11 minutes ago, alacant said:

Hi. I found by accident that this filter cut the blue halos almost to nothing. It's something to do with uv (or ir?) being recorded as visible by modified canon sensors- I'm sure someone with technical knowledge could explain far better and in more detail. 

I didn't post here because I used an eq mount but just to add support for creating a budget-have-a-go-with-what-you-have-doesn't-need-to-cost-a-fortune section, I think this is the sort of post which would fit in there. I'm gonna post the snaps here anyway in the knowledge I'm off topic for which I apologise in advance. HTH and clear skies.

Thanks for this demonstration of the filter's ability. I'm keen to try out the Semi-apo filter but need the night sky to cooperate :-)

Best Regards,
Steve

Morning,

I've gone through the code of conduct and no mention of creating new forum divisions or subject headings that I can see. There are two flavours of staff in the staff directory, Administrators (6) and Moderators (40) all of whom are contactable but perhaps the Administrator called 'admin' is the one to PM as it doesn't seem to be a person (might be wrong of course)? 

Regarding sharing things with Video Astronomy I really see three approaches as covering the whole of imaging-mainstream EQ using long exposures not achievable by other equipment, Video imaging using very short exposures and Alt-Az and some EQ imaging placed in between. Each facet has specific technical problems to overcome justifying a separate topic area. It is only very recently that members have taken up Alt-Az and lightweight EQ imaging as a keen body of people keen to experiment and developments in technology have allowed imaging using lightweight mounts possible. I know Joe Ashley faced similar incredulity on the forum he was posting his alt-Az images in as people initially simply didn't believe such images were possible. 

Cheers,
Steve

Just now, alacant said:

+1. Very well put. I'm all for having a go with whatever you have. A cheap telescope on a cheap mount is capable of far more now than 10 or so years ago. The telescopes are better for a start. It's great to see threads like this where we push the limits and experiment. Rules are there to be broken. I don't think its a coincidence that this not-an-ed80-on-a-heq5 thread is so popular!

Thanks alacant, I do think you have hit the nerve there. The one thing I have found is everyone on the thread is up for experimenting and making public the results either way. I also think technology is set to pose problems to imagers with the roll out of highly sensitive CMOS chips.

Cheers,
Steve

3 hours ago, Filroden said:

With such a low read noise it's going to be interesting seeing what can be achieved with 1000s of 1s shots. Though I can't imagine how long it would take to stack!

 

At least x50 dark frames wouldn't take long to perform, always a silver lining somewhere.

Cheers,
Steve

4 hours ago, Nigel G said:

Well said Steve.

Unfortunately admin do not seem that interested suggesting start a new thread.

Maybe I didn't explain in enough detail to get the point across. 

Hmm

Nige.

 

Hi Nige,

Thanks for all you have done on this. Much appreciated. I take it they won't/can't create a new forum title under which we can have a series of threads? Is it a lot of trouble? When at work I had rights to make new content and it could be done all the time. Don't like a tail wagging a dog even if it's a voluntary tail.

Did admin say why not? Do they feel it is covered by other topics albeit in a piecemeal, shotgun way? Can we make a case for an addition? I understand Video Astronomy had a topic opened for them some while ago. Maybe they don't, respectfully, appreciate the subject and the nuances of Alt-Az imaging and those short exposures that lie between the othodoxy EQ and EAA. 

The alternative, to start a series of threads under a specific forum division like Beginners, or more appropriately Imaging while an option would not be cohesive and runs the obvious risk of being lost as new posts on other threads arise.

The popularity of the 'No EQ Challenge' evidences the interest of the SGL membership and wider public accessing the forum and ought to be weighed by admin in coming to a decision. Nowadays decisions ought to be done in an open and fair way and against open rules and not behind closed doors or reflect the impulse of one or more person with decision making power. No inappropriateness is implied of course just my view of openness, fairness and accountability.

Cheers,

Steve