The "No EQ" DSO Challenge!

[Filroden]

Finally another clear night and a little time before the moon rises to capture a few more frames of NGC1333. In the meantime I've been playing with the scope and discovered:

- my StarSense fits my refractor after changing its mounting plate so all this time I've been fighting to do three star aligns and I could have been doing it automatically!

- I think I've figured out how to link and control my scope from within my image capture software including automatically plate solving to make re-alignment of images easier. However, in experimenting with it m mount threw a very big wobbly and would not turn off, either with the power switch or even pulling out the power cord. Very Scary. However, after a mild panic in which it looked like I'd reprogrammed the mount to be something it wasn't I finally managed to fully reset it. More experimenting needed but it could make setting up and controlling the gear from indoors much easier.

- My blue and green filter are reasonably parfocal but the red looks to be way off - not sure it matters for colour data given you can bin colour data but I need to check the luminance filter too. It could mean refocusing between filters which changes how I'd have to image.

I've also discovered that my kitchen vent blows directly across where I have to sit the scope. In these temperatures it's venting lots of steam making me worried that I'm going to suffer more from cloud pollution than light pollution.

Edited November 18, 2016 by Filroden
Added filter issues

[Stub Mandrel]

3 minutes ago, Filroden said:

I've also discovered that my kitchen vent blows directly across where I have to sit the scope. In these temperatures it's venting lots of steam making me worried that I'm going to suffer more from cloud pollution than light pollution.

You could find that hot turbulent air destroys your seeing as well... can you cap it off for a few hours?

[Filroden]

1 minute ago, Stub Mandrel said:

You could find that hot turbulent air destroys your seeing as well... can you cap it off for a few hours?

I'm going to test it first. I think it's bad now because the temperature has been dropping quickly. I'm hoping it stabilises. My HFR on the blue filter was about 2.5 so it seems to be okay.

[Filroden]

Also just discovered that using SGPro, you can track your focus by measuring the HFR for each image. I was able to (I think) improve my focus using my mask by monitoring the HFR until it reached a minimum (it worked with the spikes too). It felt better than just eyeballing the focus based on the centre spike bisecting the outer ones but the proof will be in the processing. The HFR varies between filters but I suspect that's because the stars naturally look smaller or larger depending on the filter, e.g. all light passes through the L filter so it should show the largest star size, whereas the stars look smallest in the blue filter.

Would be nice to be able to more accurately check my focus before I commit to a long night of imaging!

[Nigel G]

Ken

Glad to hear you have sorted your mount, never nice when something like that happens. 

I went to a deep sky astrophotography talk this week, apart from the usual " you need a heq5 mount minimum " it was very interesting,  the guy had a mono CCD with filter wheel and auto focuser.  He said each colour filter needs to be focused individually,  the auto focuser stores the focus for each filter and automatically focus with each filter, not sure how much they cost though.

He also said about duel band and swapping colours in processing. .. using the red as blue and blue as red which had interesting results.

Good luck for tonight,  unfortunately there's broken cloud here, getting heaver. 

Cheers 

Nige 

Edited November 18, 2016 by Nigel G

[Filroden]

8 minutes ago, Nigel G said:

Ken

Glad to hear you have sorted your mount, never nice when something like that happens. 

I went to a deep sky astrophotography talk this week, apart from the usual " you need a heq5 mount minimum " it was very interesting,  the guy had a mono CCD with filter wheel and auto focuser.  He said each colour filter needs to be focused individually,  the auto focuser stores the focus for each filter and automatically focus with each filter, not sure how much they cost though.

He also said about duel band and swapping colours in processing. .. using the red as blue and blue as red which had interesting results.

Good luck for tonight,  unfortunately there's broken cloud here, getting heaver. 

Cheers 

Nige 

I've been looking for an auto focuser but I can't find one that will fit my scope. I think I'm ok so long as I get the luminance filter focused spot on.

Clouds blew in here too. Got about 100 subs but I had to discard over half of them because of the clouds. It's now raining

[parallaxerr]

Well that was dumb!

Put the scope out a few hours ago to cool, not that a 66mm frac needs much cooling time. Did my alignment, hibernated the mount and turned everything off, including dew heat, awaiting the rise of M42.

Went back out to get started and everything's dripping wet, no drama. BUT, took the dew cap off and the objective was totally fogged over. Had to put an extra dew band on along with the normal one and put my hand warmer in the dew shield with cap back on for 20mins or so to clear the objective, not sure if that will cause imaging issues?

[SteveNickolls]

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

[parallaxerr]

Fortunately the wetness was dew not rain, so no harm done.

Here's the result of last nights attempt, second go at M42. This time I gathered more subs, although only an extra 30mins or so despite being out for an extra 2hrs. I had some serious PE (I think - major star trailing on Alt axis for 4-5 frames each time) every 10mins or so, so lots of subs got binned. Also had about 15-20° field rotation at a guess, so lots of cropping was required.

WO ZS66SD unguided on Nexstar SE 6/8 Alt/Az, Nikon D3200 w/Baader Semi-Apo filter. 198x30s subs, 50 dark, 50 flat, 50 dark flat.

 

[Filroden]

3 hours ago, parallaxerr said:

I had some serious PE (I think - major star trailing on Alt axis for 4-5 frames each time) every 10mins or so

I used to get this but I increased the weight to the back and it stopped. Now I can image for hours and it keeps rock solid on the target. 

[parallaxerr]

5 minutes ago, Filroden said:

I used to get this but I increased the weight to the back and it stopped. Now I can image for hours and it keeps rock solid on the target. 

Interesting because my setup is already very tail heavy. So much so, I was thinking of getting an ADM dovetail bar to move it forward a little.

[Nigel G]

2 hours ago, Filroden said:

I used to get this but I increased the weight to the back and it stopped. Now I can image for hours and it keeps rock solid on the target. 

This is quite interesting,  I'mhaving trouble with mine at the moment,  

There's a bit of a routine to it. I get around 10 minutes of good tracking then dump 5 minutes this keeps repeating 

The other night I got 30 minutes of perfect subs then 1.5 hours of absolute rubbish even after realigning all of a sudden it started tracking ok but it was too late to continue. 

I haven't found an answer yet.

Nige.

[happy-kat]

Would you expect to rebalance part way through a night, and does the same occur if only using a camera and lens.

[Nigel G]

19 minutes ago, happy-kat said:

Would you expect to rebalance part way through a night, and does the same occur if only using a camera and lens.

I have had the 10 minutes good 5 bad for the last 3 maybe 4 sessions,  the last being the worst. 

Not noticed it with the lenses.

I have never had to re align before or rebalance,  

Normally I would align the mount 2 star, goto object to check accuracy,  always do a sync encoder on one of the stars and go back to the object to start collecting data. 

This has worked fine in the past but something is not quite right. 

Nige.

[Filroden]

7 hours ago, parallaxerr said:

Fortunately the wetness was dew not rain, so no harm done.

Here's the result of last nights attempt, second go at M42. This time I gathered more subs, although only an extra 30mins or so despite being out for an extra 2hrs. I had some serious PE (I think - major star trailing on Alt axis for 4-5 frames each time) every 10mins or so, so lots of subs got binned. Also had about 15-20° field rotation at a guess, so lots of cropping was required.

WO ZS66SD unguided on Nexstar SE 6/8 Alt/Az, Nikon D3200 w/Baader Semi-Apo filter. 198x30s subs, 50 dark, 50 flat, 50 dark flat.

That's a really good image with a clear man running! I do like the field of view on your WO. Frames it nicely.

[Filroden]

You've all cursed me. Having not dropped a sub for tracking for I don't know how long...after 45 minutes tonight my tracking just stopped and I couldn't get it going again! I suspect battery issues but I need to investigate further.

[Nigel G]

Oops sorry Ken.

I think I might have and idea what's making mine play up, could be the altitude clutch, I won't know until the next time I use it as I have loosened it up when cleaning it a couple of days ago. 

Hmm I wonder. 

[happy-kat]

I wonder if it is better if your object is higher then the check you do so the mount ends finding the object on an upward movement.

[parallaxerr]

2 hours ago, Nigel G said:

always do a sync encoder on one of the stars and go back to the object to start collecting data

I found this made my goto accuracy worse. For some reason, after syncing to a nearby star, the goto to the target object was not repeatable, neither was returning to the sync object? Auto two star works best for me, then straight to target, take one sub, adjust framing then start collecting.

1 hour ago, Filroden said:

You've all cursed me. Having not dropped a sub for tracking for I don't know how long...after 45 minutes tonight my tracking just stopped and I couldn't get it going again! I suspect battery issues but I need to investigate further.

I reported a judder in the alt axis to FLO just recently. Martin was quite explicit about using 13+ volts for a supply. Ensuring I have at least 12V reduces the effect but it still happens occasionally, so these mounts are obviously voltage sensitive. I guess you have little option with the Evo internal battery though. Can you use external power too?

1 hour ago, Nigel G said:

I think I might have and idea what's making mine play up, could be the altitude clutch, I won't know until the next time I use it as I have loosened it up when cleaning it a couple of days ago. 

Good shout Nige, I did the very same about  month ago after a re-grease to the main gear. Last night was by far the coldest I've imaged in so maybe a little contraction in the clutch let things slip. I just grabbed the OTA and it moved in Alt, not easily but readily so you may be on to something. My star trails were straight up, which agrees with this theory - where's that spanner...

[parallaxerr]

Made a few changes to my set up last night as a result of the discussion above. 

The WO OTA has an L bracket attached which has a vixen dovetail form. It's neat but doesn't allow me much adjustment. I dug out a 7" dovetail and eventually found some bolts to fit as the two required are different threads!!! One bolt goes through the dovetail and attaches to the L bracket photo tripod adapter which is 1/4-20UNC and the other goes through the dovetail and L bracket and screws into the OTA, think its a UNF thread.

I had to remove the plastic trim around the dovetail clamp as the focus knobs inerfered, but now I have full freedom to slide the scope fore and aft.

The result is that I'm now balanced slightly objective heavy. Hopefully this means the Alt gear is always under load and driving the scope up instead of allowing it up, as it was when tail heavy, if you see what I mean? Also, I now have no Alt restriction 

The clutch was also a tad loose. Whilst there was some friction between the plates, there was barely any torque on the nut so that's been tweaked up. Hopefully less binned subs next session.

 

[Filroden]

1 hour ago, parallaxerr said:

Made a few changes to my set up last night as a result of the discussion above. 

The WO OTA has an L bracket attached which has a vixen dovetail form. It's neat but doesn't allow me much adjustment. I dug out a 7" dovetail and eventually found some bolts to fit as the two required are different threads!!! One bolt goes through the dovetail and attaches to the L bracket photo tripod adapter which is 1/4-20UNC and the other goes through the dovetail and L bracket and screws into the OTA, think its a UNF thread.

I had to remove the plastic trim around the dovetail clamp as the focus knobs inerfered, but now I have full freedom to slide the scope fore and aft.

The result is that I'm now balanced slightly objective heavy. Hopefully this means the Alt gear is always under load and driving the scope up instead of allowing it up, as it was when tail heavy, if you see what I mean? Also, I now have no Alt restriction 

The clutch was also a tad loose. Whilst there was some friction between the plates, there was barely any torque on the nut so that's been tweaked up. Hopefully less binned subs next session.

Oh to be back in the spot where I was not alt limited! My SCT with DSLR easily clears the base but the refractor and the much longer camera train now are far too long. I also only have a short dovetail and it is very tail heavy. I may have to see if I can do something similar.

Hopefully your tracking will be spot on now.

I'm going to check my mount over. I'd forgotten how cold it was last night so it might just be the changing temperatures?

[parallaxerr]

On 18/11/2016 at 18:14, Filroden said:

my StarSense fits my refractor after changing its mounting plate so all this time I've been fighting to do three star aligns and I could have been doing it automatically!

 

How does the starsense cope with an alt limitation? Despite getting good alignments, I've been fancying one for the plate solving, but I thought I may get a mount conflict if it's free to slew where it wants.

[Filroden]

9 minutes ago, parallaxerr said:

How does the starsense cope with an alt limitation? Despite getting good alignments, I've been fancying one for the plate solving, but I thought I may get a mount conflict if it's free to slew where it wants.

I can set slew limits plus I use it manually as I have limited views. You can save your three manual areas as a user defined program so you can reuse it if you set up in the same spot each time.

its one downside is that you do lose alignment a little each time you remove it from the mount as you can't put it back in the view finder slot quite the same each time. But my target is still in the centre of the frame and a small manual slew gets it where I want it.

Edited November 20, 2016 by Filroden

[parallaxerr]

5 minutes ago, Filroden said:

I can set slew limits plus I use it manually as I have limited views. You can save your three manual areas as a user defined program so you can reuse it if you set up in the same spot each time.

its one downside is that you do lose alignment a little each time you remove it from the mount as you can't put it back in the view finder slot quite the same each time. But my target is still in the centre of the frame and a small manual slew gets it where I want it.

Like the sound of that Ken, especially the user defined areas. More functions than I realised. 

Dear Santa......

[Filroden]

5 minutes ago, parallaxerr said:

Like the sound of that Ken, especially the user defined areas. More functions than I realised. 

Dear Santa......

It's worth taking a look at the manual http://www.celestron.com/media/1317936/94005_starsense_autoalign_manual_february2016.pdf