Grifflin

Hi All

I have been struggling to collimate my RC 8 and, whilst I have sort of got it, I have (unsurprisingly) discovered that the compression ring on the stock focuser leads to inconsistent results.  What I think I need here is to be able to have a threaded connection all the way through the image train.  Any advice on how to achieve that?

Neil

On 01/12/2021 at 01:36, jhart said:

Hi,

Here is the link to the Youtube video I mentioned: https://www.youtube.com/watch?v=AnE5ikgzX7s  

 

Thanks Jhart....apologies for the delay in replying, only just saw your post.  Checked out the video...to be honest, my  RA balance seems to be ok so I'm loath to start messing with it just yet.  I'm sorting out something for the Dec saddle first (not done yet) to see what difference that makes.

Neil

I got the RC 8" f8 last year but haven't used it in anger yet.  I did put it on the mount and have taken some images (M101, M51) just to work out balance , back focus etc.  Since then I have taken the plunge and finally got round to collimation which , worryingly, I found fairly straight forward....so I have probably done something wrong!  Haven't had a chance to use it since collimating but it will be on the mount for the next clear night.  Planning on imaging Mel 15 to compare with the images taken with the SW 80 ED.  I'll let you know how I get on.  Equipment as per signature.

Neil

I've got a ZWO 294MC paired with my SW 80 ED and it works well for me.  Amp glow calibrates out and my flats work just fine even when I'm using the L-Extreme.  I guess it's personal choice on the square format.

Neil

Hi Tom

Retaking your darks or doing  a bad pixel map should sort it. User manual will tell you how.

Neil

I'm far from being an expert but the star profile looks like it might have locked on to a hot pixel?

Neil

As a beginner in this hobby I have found this tool easy to use and the results easy to understand.  For what its worth, from my perspective I think:

1)   The tool MUST continue to be easy to use and the results easy to understand for a beginner.

2)  If the accuracy of the tool can be improved given the theoretical and practical knowledge that is self evident in this thread then it will be an excellent tool indeed.

3)  Any limiting assumptions (e.g. diffraction limiting, mount performance etc) must be called out.

I think this is what @vlaiv is driving at by starting this thread.

Also, whilst I understand the maths, I don't yet completely get the concepts behind it but that it something I will work on and having it played out in this thread  (including the broader discussion) is extremely helpful.

Very happy to be involved in any user testing if @FLO decides to make changes.

Neil

....and one more

41 x 300s (about 3.4 hours).  Equipment:  SW 80 ED,  ZWO 294 MC Pro, L-Pro.  Image capture with NINA and processed in PI.  Only  posting the Luminance channel just because I like it.  

Neil

Hi Everyone

48 x 180s lights (so nearly 2.5 hours).  Equipment:  SW 80 ED, ZWO 294MC Pro, L-Extreme.  Image capture using NINA and processed in PI.

Neil

@Sterrenland  Great image.  I'm guessing you used a filter with the moon out?  Which one did you go for?  Just asking as I'm hoping to capture M42 as soon as we get a hole in the clouds.

Neil

Hi All

Western Veil and Pickering's Triangle  processed as HOO in PixInsight

SW 80ED, ZWO 294MC, L-eXtreme

45 x 240s subs (Total 3 hours)

I was really taken by how much and how strong the O3 component came out.  The Ha was also really strong.  So didn't mess with any changes to saturation or hue.

Critique and comments welcome  

Neil

Edit:  Should have mentioned that when I combined the Ha and O3 using LRGB Combination, I used the O3 as the luminance rather than the Ha.

I have had a similar issue with my 294mc and processing everything in PI.  Today I use  Flats, Dark Flats and Darks for my calibration (so no Bias frames) and, in PI, I turn OFF Dark Optimisation.  Cleared up the problem for me.

Neil

Thanks Both....yep, looks like there is a fair variation of distance data out there.  I looked up IC 1805 on Simbad and there are four measurements: three in the range 1.7 kpc to 2 kpc and a fourth at about 6.1 kpc.  So about 5,500 to 6.500 ly if you ignore the fourth one.

I think the learning here for me is double check distance measurements in Stellarium before quoting them  

Neil

Hi All

Has anyone noticed that in some cases, the distance to targets selected in Stellarium don't seem to agree with other sources?  ....or the other way round!  ....and I'm talking differences outside of the "error bar".

For example, the Heart Nebula (IC 1805) is quoted as aprox 2,500 ly in Stellarium but in Wikipedia it is aprox 7,500 ly.   Also, if you look at the Christmas Tree Cluster (NGC 2264), Stellarium has that at about 1,200 ly but Wikipedia at 2,350 ly.

Is it just me?

Neil

Hi All

This is my first time on the Heart Nebula.

SW 80 ED,  ZWO 294MC,  L-eXtreme filter, 60 x 300s subs (Total 5hrs). Processed in HOO with PI.

For some reason, I struggled on the processing with this and in particular issues with artefacts created by Starnet.  However, got to the point where I'm reasonably satisfied so here it is.

Critique and comments welcome.

Neil

22 hours ago, jhart said:

I have seen a YouTube video which claims this DEC balance problem can be solved by angling the counterweight bar slightly.  Has anyone had success with that method?

Not seen that....have you got a link?

2 minutes ago, Stefek said:

Yes, I have Esprit 120 and with guiding scope, filterwheel, autofocuser  it is almost impossible to balance it only by moving counterweight on RA and shifting scope backward and forward , so that with disengaged RA and DEC , the scope stays in any position that you push it to.  One need so called 3D balance , adding additional counterweights on DEC and also on RA .(i also have additional weight on RA, which I made by drilling the hole in my counterweight, made thread in it , and screwed in a bar with some weight on it . That additional bar is perpendicular to main counterweight shaft. My balancing sequence is:

1.  put RA axis to horizontal position , and align the DEC axis so that scope stays horizontal. (only by moving the scope backward or forward) 

2. Keeping that  position will move counterweights so that it gets balanced along RA axis.

3. At that point I have the system balanced in horizontal position. Will move it to "home" position. I lock DEC and will move RA , if it does not stay , I rotate the counterweight with additional bar on it until RA stays wherever I put it.

4. Then I lock RA and if DEC does not stay where I push it, I would move DEC counterweight  in or out  until DEC stays whetever I put it.  After all I just check whether it all stays wherever I push with both axes disengaged. 

 

 

Got it...thank you.  😀

16 hours ago, Stefek said:

The mount itself will deal with that , especially with relatively light scope. I have just taken 8mm threaded bar, cut it to about 20cm and screwed into the hole on DEC saddle . 

Asked my neighbor to cut me few pieces of steel with 30mm diameter with various lengths (from 5 to 50mm) and drill it and make the thread in the center. 

Now I have various weights that I can just screw closer or further and balance the scope 

(Esprit 120 or Edge HD 8 )perfectly .  I regularly have guiding RMS in 0.4-06" range.

Thanks Stefek

Just for clarity, are you saying that you have also had a similar issue and you have used a small counterweight on the saddle to correct it?

Neil

Hi All

I have an iOptron CEM 70 mount and while the RA balances just fine, the Dec axis balance is weird.  If the balance is way off then it behaves as you would expect when it is front or back heavy.  however, as it gets close to balance it settles at about a 35 degree angle to the West.  If I push it further West it will return to its 35 degree position as if it was back heavy but if I push it in an East direction it returns to its rest position as if it was front heavy.  If I move the scope forward or back from this point it seems to push it into an unbalanced state.

Now, I have heard about Z axis balancing and I see that iOptron have a Z axis balance counterweight which has a very short counterweight shaft which screws onto the side of the saddle (there is a screw hole on either side to accept this).  I'm not really clear what this does and if it would help me to get a 'proper' balance in Dec.

All that said, my guiding seems to be ok (0.7 - 0.9 arc sec/pix) with a SW 80ED on it but if I put a heavier scope on it and start to work the mount a bit more, is this balance weirdness going to start to hurt me?

OR....am I missing something and making a newbie mistake?

Really grateful for any thoughts or insights here please.

Neil

TV viewing in my household is somewhat Darwinian....if its good then it survives.  Having watched the first episode its spot has been replaced by "Young Sheldon".......Hmmmmm....

Neil

14 hours ago, newbie alert said:

It's in Orion..  astrometry solved it as m78, which is what I said...

Apollogies...my mistake....I had actually aimed at LDN 1627 but just seen that tis is part of M78 🙄.  So yep...completely correct 🙂

Neil

1 hour ago, Craney said:

Maybe the Pac-man  ....  NGC281     ???

Good guess but not the Pac-Man 🙂

10 hours ago, newbie alert said:

Oooh, guess the target time .... I'd say casper( m78) with a 183 camera .... 

...nope!

Its near constellation Orion.

Sure....ZWO ASI294MC

Edit:  My first light with the L-Extreme I posted up here 

I ended up going down the L-Extreme route albeit with a dedicated astro camera and Bottle 4/5 zone.  I found it particularly effective when the moon is out.  In my limited experience I found the results to be impressive.

Neil

11 hours ago, Craney said:

No  probs.  

I'm now trying to figure out what object you were imaging ??

55 minutes ago, newbie alert said:

Oooh, guess the target time .... I'd say casper( m78) with a 183 camera .... 

LOL....happy to hold off on the target if anyone else want a guess 🙂.

Equipment was a SW 80ED x0.85 with a 294MC and L-Extreme filter.

I had been imaging the Heart Nebula earlier in the night and this was a target of opportunity as I was not confident about whether or not clouds would roll in.  More of an experiment in setting different targets in NINA, Meridian flip and autofocusing all whilst asleep.

Neil