Peje

Glad to find this topic... going to make the switch now

My only issue with PS2 was that my initial solve almost always fails (100 search limit) and falls back to online solver, which last night was offline!

Thanks. I ended up returning the BH as I couldn't get focus.

I keep thinking out buying a BH zoom lens for visual astro in the summer, someday maybe :)

36 minutes ago, Starflyer said:

Be careful of tightening them too much, the bearings quickly wear through the anodising on the drawtube leaving you with very rough movement. Not that I've done this of course 🤥

For my tightening, I used a metric Allen key and stopped at the point where it was about to slip. Hopefully this isn't excessively tight...

I priced replacing the focuser... I'd forgotten how expensive they were!!

Ron replied immediately after I posted this topic... excellent support as always. He confirmed:

- You can't use the fine focus wheel with motor kit fitted (even if the clutch is disengaged)
- You can use the coarse focus knob when the motor clutch is engaged.

So this was a red herring!

I went back out and tightened up the lifting capacity bolts, tightened to the point I could feel the focus knobs were harder to use and also as tight as I dared using metric allen keys! Then some tests:

> I marked the manual focus knob and moved the focus in and out by 1000 steps, 20 time... no focus slip on the knob.
> I lined up a spec of dust on the focuser tube and moved the focus in and out by 1000 steps, 10 time... no focus slip on the focuser tube.

So, either adjusting the lifting capacity resolved the problem or I haven't figured out what the problem is yet!!

Will have to do some more testing the next time we get some clear sky... see you in 2021

Pete

Hi Folks,

I've encountered a slight issue with my now 4 year old CR2, I noticed that the inward travel seems to be slipping. Oddly it seems to slip more when the adjustment bolts are facing downward than when they are upward.

I use the motorised kit and noticed that my last two session as the night grows colder that I start to have focus problems. I have adjusted the lifting capacity screws but this doesn't help, when I release the motor clutch and manually focus with the coarse wheel it works as expected but when I use the fine wheel I have problems with it slipping.

Something that I may be remembering incorrectly was that when the motor clutch was engaged, you could not move the focuser using the manual focus knobs. Currently you can.

Has anyone had problems like this before? I'm wondering if it needs stripped down and cleaned. I have emailed Ron @ Moonlite for help.

Pete

I've never attributed rings to be down to the CC but that's perhaps because I haven't thought of it. I'd like to see some comparitive images. 

This is a well known, challenging star for all scopes. 

The problem I had with the Baader CC was that it was causing my stars to bloat. This could have been because my scope is f/4 but it does seem to be a widespread problem when you start search the internet for it. 

EDIT: Just noticed you're also running f/4. Mine is the SW Quattro. If it's the same I would suggest getting the CC made for the Quattro. 

1 hour ago, andrew s said:

Life is full of annoying constraints. However, I don't see any way camara angle can impact field rotation.  Framing yes rotation no. I rotate my camera/spectrograph to avoid overlapping spectra with other stars. The orientation stays fixed all night with an eq mount but for the 180 deg turn on the meridian flip which I take out with the rotator.

Regards Andrew 

I can offer no explanation as to why but the further my camera is away from 0/180deg orientation on the OTA, the more rotation I seem to get over a nights image.

This is fairly anecdotal evidence as it was within the first couple of years of my AP so I was adjusting numerous things in unison.

I discussed using the SA200 low profile filter with Robin a few months back, he recommended using the SA100 in my system.

I'm currently trying to think if I could rotate my entire camera train by say 15deg and then move the camera by -15deg. My main constraint is that I need the camera sensor to be parallel to my scope axis to stop image rotation during long imaging sessions but also that if the FW get's too high it might clash with the roof of my roll off shed.

22 minutes ago, Helen said:

On the question of alignment, I added a little plumbers tape to the filter thread which allowed me to vary the rotation of the filter in the filter holder while still being secure.

Helen

That's a good idea, I had been thinking of something like that. My main problem is that there is no spare height in my FW so if I unscrew the filter even slightly I will risk it scraping the inside of the casing.

@robin_astro I've just fitted the SA100 into my system and grabbed a few images of Capella last night, that's as far as I've got unfortunately! A couple of queries / problems I have:
 

- I use an IDAS P2 LP filter, I presume this will create holes in my spectrum?

- The SA100 is running at a slope and I cannot rotate my camera without screwing up other alignment or hitting the filter-wheel off the shed. Is this going to be a major problem?

I need to go through the search  options, I don't have all of those in my list.

On 17/09/2019 at 20:52, Marvin Jenkins said:

JamesF, you the man. I am always fearful of going into settings and background areas as I am old before my years. A sad legacy of being the generation between pre computer and everyone has a computer age, I try my hardest, but somehow I like a printed page.

I am 47, my school had four BBC Micro’s but no pupil was allowed to use them as they were very expensive. So don’t blame me.

Marv

Did you ever get this added? I've been trying tonight but it's not showing up on the search, just says 'unknown error'.

Just now, Merlin66 said:

Yes, the SA 200 is designed to better fit the filter wheel.

you also should look at orientating the grating to present the Spectral image horizontally across your camera chip.

 

Do the warnings on the RSpec calculator not cause concern?

Just now, Thalestris24 said:

Can you not just use a dslr+lens+adapter as per the web page? https://www.rspec-astro.com/star-analyser/

Louise

I want this to be part of my main imaging system.

The intention is that at the start, middle or end of a night; the system will select the SA filter and go to my SA target, auto-adjust the focus position and then capture the data I want before moving on with the rest of my imaging run.

1 minute ago, Merlin66 said:

As I said, one of these life compromises........

I’d still go for the 200 l/mm.

 

Absolutely, nothing is ever black and white...

To be clear, do you think the SA200 is better suited to my current system?

1 hour ago, Merlin66 said:

Pete,

26mm is a very short spacing, I’d say the SA200 would definitely be a better bet. Could you fit a spacer between the filter and the camera to increase this spacing?

This is always the compromise when trying to use gratings in filter wheels ( and other photo metric or AP applications)

I have one set-up where a 207 l/ mm grating mounted in a Neumann filter drawer in front of a flip mirror ( to allow accurate setting on the target) then the camera - works out about 60mm. This gives a good Spectral image for the camera I used Atik16.

(Edit) Pete, I think you have entered the wrong camera chip width in the calculator - must be more than 193 pixel???

Unfortunately I can't add spacers, I need this to drop into my existing system. I often use this when I am away from home (or in bed sleeping) so I need to avoid having to physically access the system.

The 193px is actually 1931, the mobile phone display for the RSpec website has just chopped the edge off it, you can see the top of the 1 just poking through in that screenshot.

The attached screenshots show that the calculator states the SA200 is worse for me than the SA100.

For reference, I've attached the input and output from the RSpec calculator 

EDIT: Updated screenshots in later post.

5 minutes ago, Merlin66 said:

Just check the spacing between the grating and the camera chip.

The SA200 is recommended where the spacing is limited...

I use the SA100 at around 60mm spacing and a 207 l/mm at around 40mm.

This determines the dispersion, the length and brightness of the Spectral image.

I use John’s BASS Project for all my processing. Well worth checking out.

Pete, mono is best. You can always colourise the Spectral image after calibration.

ken

 

Hi Ken,

My camera has 13mm spacing plus roughly half of the 25mm filter wheel so I estimate around 26mm spacing. 

The SA200 gives me two red boxes, one being the focal ratio and the other I cant remember. 

The SA100 gives me two green boxes and a warning that the focal ratio could risk lower resolution. I cant increase the FR as I need this filter to be part of my normal imaging rig.

Hi Robin,

Apologies if this is a daft question... my CCD is mono. I assume this has no bearing on the SA, in that the spectrum is amplitude based and constant length ratio rather than being defined by colour?

Pete

7 hours ago, robin_astro said:

About the Star Analyser, yes but don't ask me to solve Brexit 😉.

Yes there are other software packages around like Visual Spec which RSpec is based on, BASSS and ISIS  but my advice would be to not get too bogged down with the processing side initially and just look at a few interesting stars. One of my favourite Star Analyser images is this one by Christian Buil

from his website here

http://astrosurf.com/buil/staranalyser/obs.htm

Even without any processing there is a huge amount of  astrophysics revealed in that one image.

 What equipment do you plan to use?  (The ATIK428EX on your equipment list for example is an excellent camera for spectroscopy. I use one on my ALPY faint object spectrograph)

EDIT: that plus your 200mm f4 Newtonian would work really well with an SA100

Cheers

Robin

Hi Robin,

Excellent info there, it sounds like this really is something I'm after. 

I will be using it be the f/4 newt, the calculator on the RSpec website does warn me that f/4 has a risk of reduced resolution but it's not a red flag and even an increase to just f/4.5 turns it green.

I just need to check that the SA100 will fit in my SX filter wheel but as it takes normal 1.25" filters I expect it will be fine. 

The calibration and processing doesnt worry me, I actually quite enjoy that side of things.

Just now, Thalestris24 said:

I meant the calibration and processing you have to do after you've got you star diffraction grating image. You have to use the calculator on their page and read the guidance. I think it works quite well with a camera + lens + adapter as per their example on the web page. 

I'm keeping mine for now

Louise

No problem

yes I skimmed through it earlier, I think it should be ok. My plan would be to grab a few star images at the start of a session so I have something to play with in between proper images. 

3 minutes ago, Thalestris24 said:

Hi

Um, I'm afraid I never really did much with it. You have to spend some time doing the calibration/post-processing (https://www.rspec-astro.com/more-videos/ ) and I didn't really have the patience. Plus I so rarely get clear skies. I've tended towards imaging via mono live stacking with the qhy183m instead. Maybe I'll go back and look at the sa100 again one day.

Good luck if you have a go!

Louise

Ah, I get that, it's hard to use clear sky for setting up and calibration.

Just a thought, I would certainly buy the SA100 from you if you be interested? I was hoping to get one second hand in case the focal ration proves to be a problem.

I've been considering getting one of these for a while, my setup isn't ideal because it's f/4 but it gets 2 green flags and just a warning on the focal ratio rather than a red box so I guess this could be worth a try.

Louise,

How useful have you found this? I've been thinking it could be fun to catalogue lots of stars and their makeup.

1 hour ago, retret66 said:

happened to me once in a while which took me about 1 month to fix. Mount is sticking due to overtightened worm gear assembly. DEC will run away and comes back. By loosening the allen screws and tuning it, it was gone. The saddle will actually wiggle if overtightened and tight when loosened..I have a CGX mount

I don't think it can be the same issue for me, I have quite a large amount of dec backlash (on purpose). 

That's said, I plan to reduce that significantly this week.

20 hours ago, tooth_dr said:

https://secure.investni.com/static/library/invest-ni/documents/northern-ireland-space-strategy.pdf

 

https://www.siliconrepublic.com/companies/robert-hill-northern-ireland-space-office

 

@Peje Robert Hill wouldn’t be a bad starting point. 

Excellent info  

Will have a read at those and then reach out.