ST80 Mods for Imaging

[Gina]

Some more small changes to the design but I think I shall wait until I have a fully working system before I post any more details.  Unless, of course, anyone really wants a blow by blow account of my workings   I keep thinking I'm nearly there when something else crops up

There's cloud tonight so no imaging but I do have some data from last night to process.  Working with Ha and OIII only - I need better alignment and a better camera for the SII and a three scope rig.  I have the third 460EX on order from FLO (ordered Sunday evening) and waiting for them to receive the goods from the distributors before they can send it to me.  I have the two scopes quite well aligned but I broke the plastic gear on the alignment adjuster on the third.  The new alignment adjusters use threaded stainless steel - stronger and with finer adjustment

[Gina]

Well, I'm still at it - rebuilding my imaging rig, that is   It seem to take me a long time to do metalwork these days. 

[Gina]

I think I have the final design (famous last works)

The only change is in the plastic spring which I've combined with the bearing block for the RA threaded rod adjuster to save a mounting point.  On test, this system seems fine though of course, "the proof of the pudding is in the eating" and I'm hoping to get it set up this afternoon.

Here are some photos...

The ST80 mounting plates fitted to the 450mm x 250mm x 10mm main mounting plate (mistakenly described as 400mm long in earlier posts).  The latter is screwed to the ADM dovetail bar that goes on the EQ8 mount.

This photo shows the focussing mechanism.

The Dec alignment adjuster screw - turned with Allen key.  I could have added a knob but since this is only a one off adjustment I thought it wasn't needed.

[Gina]

Mounting system and four telescopes installed on EQ8 in the observatory - took about an hour's fiddling   Everything just fits but I had to loosen a fixing screw for one of the ST80s to get the scope past the MN190 scope ring.  Now indoors for a break and refreshments   Particularly a nice cuppa

[Tinker1947]

Well done, nothing like a nice cuppa tea.......

[Gina]

All set up and all working   And working well   The alignment adjustments work very well   I don't even need an Allen key to adjust the Dec - I can turn the head of the screw with my fingers quite easily.  It would be quite possible to get it to the nearest pixel but I've lost the daylight now so will slew from my distant treetop to a celestial object

[Gina]

Espri 80ED with 460EX no.1 and 3nm OIII filter

ST80 no.1 with 460EX no.2 and 5nm Ha filter

ST80 no.2 with 314L+ and 5nm SII filter

[Gina]

AT is working again now.  Used Ha on the ST80 defocussed. 

Still no 3rd 460EX so using the 314L+ for SII with 5nm Astrodon filter and in view of the low res image given with binning 2x2, I'm going to try unbinned.  Probably using 20m subs to make up the same number of photons captured.

There is cloud about but it's clear where I want to image

[Gina]

In fact 10m seems to give near saturated stars unbinned. 

Here's an ST80 5nm SII filter 10m single sub with slight processing in PS and resized for posting.  Unguided.

[Gina]

Cloud now - waiting for it to clear, which it's forecast to do.

[Gina]

Dratted hail shower just gone over   Had to dash out and shut the roof (had to whip the dew shield off the MN190).  Stopped now so I guess I'll go out again and open up.

Been thinking that when I'm not wanting to use it for imaging, it would be better to take the MN190 off and replace it with a smaller guide scope (or set up an OAG).  That would mean I could close the roof without parking the mount.  It would be easy to add the OAG to one of the ST80s as I'm already using around 60mm of extension tubes.  One of the Evostar 80EDs would make a good guide scope too.

[Gina]

I've now processed the data from 2/12/14.  35 Ha subs of 5m binned 2x2 and 23 OIII subs also of 5m binned 2x2.  Stacked in DSS, stretched in PS, aligned with RegiStar then combined and processed in PS in HOO palette.

[Gina]

Even between batches of cloud the transparency was/is poor tonight and I haven't captured any decent data   So I've packed it in for tonight and shut everything up.

[happy-kat]

Another day :-)

[Gina]

My new 460EX should arrive Monday and I've been looking at the weather forecast.  Monday night seems to be alternating between clear and cloudy in the forecast, so who knows?  Nobody until Monday night actually arrives I guess    The local forecast for last night changed hour by hour - sometimes clear and frosty and sometimes heavy showers.  Well, we got all sorts as it happened   A couple of hail showers, some cloud, sometimes a completely clear sky.  I guess it's really best not to bother trying when there's a hint of clouds or precipitation but if I did that I'd never get anything

I think what's really needed is an automatic system that reads the sky and opens/closes the roof and parks/unparks and slews this way and that but I'm not reallly up to all that   I could downsize my main rig so that I don't have to park it to close the roof.  I only use the MN190 for imaging during galaxy season mainly so that could come off a lot of the time and then the roof would clear the rig on it's travels.  Maybe I should do some more thinking

[Gina]

Well last night's data turned out better than I thought   Ha 10x10m, OIII 13x10m and SII 13x10m all unbinned.

Hardware - Ha ST80 460EX - OIII Esprit 80ED Pro 460EX - SII ST80 314L+  Guiding with MN190, OAG and Lodestar X2 3s integration - PHD

Data captured with Atik Artemis Capture in three instances.  Stacked in DSS, stretched in PS and aligned with RegiStar then combined and further processed in PS using Noel's Actions etc. cropped and slightly resized for upload here.  Saved in PNG format.

[Gina]

Actually, very careful examination of the data from the second ST80 shows it needs slight attention - there is a sign of optics pinching on the stars.  It also needs the edges of the lenses blackened.  The results show the performance of the telescope as received.

This is a portion of the stacked SII subs at full size (pixel for pixel).

[Gina]

I now have the new ST80 indoors and taken apart.  Well not totally taken apart - I have the lens cell off the body but the lenses are screwed in so tight that I can't unscew the cell.  No wonder the optics show pinching!   Think I'll try warming up the plastic lens cell with my small hot air gun and see if I can get it unscrewed.  The cell consists of two plastic parts that screw together with about a 3" thread (80mm plus I guess).

[Thalestris24]

I now have the new ST80 indoors and taken apart.  Well not totally taken apart - I have the lens cell off the body but the lenses are screwed in so tight that I can't unscew the cell.  No wonder the optics show pinching!   Think I'll try warming up the plastic lens cell with my small hot air gun and see if I can get it unscrewed.

Unlike in Dion's video, I've never been able to undo mine either! I decided to just leave well alone...

Louise

[Gina]

Thanks Louise but unfortunately all isn't well - I'm getting severe pinching.  I'll just have to be careful   I'll have a good think about it.  Applying warmth to the outer part of the casing might provide some differential thermal expansion and loosen the thread.  Just hoping it isn't glued - the other one wasn't.

[Thalestris24]

Thanks Louise but unfortunately all isn't well - I'm getting severe pinching.  I'll just have to be careful   I'll have a good think about it.  Applying warmth to the outer part of the casing might provide some differential thermal expansion and loosen the thread.  Just hoping it isn't glued - the other one wasn't.

I'll be interested to hear how you manage it! Actually, what I said was wrong - it's the dew shield I've never been able to get off!

[Stu]

Thanks Louise but unfortunately all isn't well - I'm getting severe pinching. I'll just have to be careful I'll have a good think about it. Applying warmth to the outer part of the casing might provide some differential thermal expansion and loosen the thread. Just hoping it isn't glued - the other one wasn't.

Is this one not under warranty Gina? Can't you get it swapped?

Sent from my iPhone using Tapatalk

[Gina]

Is this one not under warranty Gina? Can't you get it swapped?

Sent from my iPhone using Tapatalk

Yes, I expect I could get it swapped   I did think of that but it only needs unscrewing.  I know Steve/FLO would be quite willing to swap it

[Gina]

I'll be interested to hear how you manage it! Actually, what I said was wrong - it's the dew shield I've never been able to get off!

Both my dew shields just pull off.

[Thalestris24]

Both my dew shields just pull off.

I know they're supposed to but mine won't. Never mind.