Clarkey

You could consider an L-3 filter which narrows the spectrum down a bit. Also, look at your processing, you may be able to reduce the stars with slightly different methods. 

FWIW I set up an AZ-EQ6 with a RC8 and guide scope each time I image so it is doable. The larger mount also tracks better than the HEQ5 - whether that is by luck or design is another matter. I would not really call a 6 class mount 'portable' though.

There are lots of very good doublet refractors such the ED80 and 72. You can also pick them up second hand quite cheaply with FF's. I have and ED80 and it is excellent for the money. If you went second hand on the OTA it might leave enough in the pot for a used astro camera. Have a look on Astro buy and Sell - there are some on there now including a 61mm Sharpstar triplet with FF for under 500 pounds. Ideal if you are not guiding.

7 hours ago, ollypenrice said:

I've used dual rigs for many years but always with two PCs

I did think of this but I really need to dither with the dslr. If I get a new astro camera it might be less of a problem.

7 hours ago, scotty38 said:

Not only can you chose  one of two ASCOM driver instances in NINA you can run two discrete instances of NINA and set it up to run the Profile Chooser at startup

This was my plan. Just need to work out NINA choosing the right bits of kit.

I'll give it a go and see what happens.....

I am in the process of setting up a dual imaging rig. Good nights are so hard to come by I want to take advantage of every opportunity and increase my imaging time. My question is relating to focusers.

I have two Sesto Senso focusers which I want to use through NINA, but I am wondering how I identify each one and connect to the right one when running two instances of the software. (One slave and one master). Does anyone know how I ensure I connect to the correct focuser through the USB ports?

It's worth looking at this video by Dr Robin Glover - Sharpcap creator.

https://www.google.com/search?q=dr+robin+glover+astrophotography&oq=dr&aqs=chrome.5.69i60l2j69i57j69i61j69i60j35i39l2j46i199i433i465i512.2130j0j4&client=tablet-android-asus-tpin&sourceid=chrome-mobile&ie=UTF-8#

Gives quite a good run through of sub length selection.

Just to add to the good advice you have already been given I'll add my tuppence worth.

I agree that an EQ mount is definitely the way to go for imaging. If you like visual as well then the AZ-EQ5 is a good option. I have an AZ-EQ6 which I use for AP but on the occasions I do visual I convert it to AZ mode. Particularly useful for newts. EQ set up is easy enough - don't let it worry you. Worst part is the dirty knees - which is why I got a ipolar.

On the control options, I use a Mele Quieter 2 mini PC with added storage. I have two of them on different rigs and they have been excellent. They also seem to have a reasonable wifi range.

4 hours ago, catburglar said:

I’m not an expert imager, but I think I’d put the 1600 on the reflector… this way you maximise both the resolution of your luminance dataset and the ‘speed’ that you collect the signal.

You can capture the colour data at lower resolution and tolerate a lower SNR in your colour data and this will (I think) have less impact on your final image…

Although you will lose a bit of FoV (approx 1.8x1.2 degrees with this approach versus 2.0x1.8 if you put the ASI on the frac). 

Having debated in my head for a while I have decided on a different approach. For a couple of reason I have decided not to use the newt. Firstly trying to blend and remove stars with and without diffraction spikes is likely to be a pain. Secondly, when I get the new camera I can use the DSLR on the Newtonian which hopefully will remove some of the reflection issues I have had.

For now I will get the luminance data from the 90mm triplet and the colour from the ed80  with an L-3 filter. It won't be quite so fast but will hopefully still give good results.

I am in the process of setting up a widefield dual imaging rig to take advantages of the rare clear skies we have in sunny Cumbria. The question I would like to ask is what is the best combination of scope / camera? I currently have 3 scopes of similar FL - a SW ED80 (510mm with FF), a StellaMira  90mm triplet (540mm with FF) and an F4 6" reflector (600mm). These will be combined with a ASI1600mm pro and a Canon 600D (although this will hopefully be upgraded in the summer to an IMX571 based OSC - 'accountant' permitting). My initial thought is to pair the 90mm triplet with the ASI1600 for luminance data and use the Canon 600D with the F4 reflector for the colour. The slight increase in sensor size will in part offset the longer focal length. Is this the best option or should I use a different combination? Also, with the new more sensitive camera would this still be the better combination?

Any thoughts would be greatly appreciated.

Just as an additional piece of info the 0.8x reducer can be put on the wrong way round as it has the same thread at each end. If your spacing is correct at 55mm try reversing the field flattener.

The 130 is certainly capable. I only ever image one target per night and am able to leave my kit out so never have less than 6 hours integration time. Quite often for faint stuff it will be more than one night. Makes all the difference. F4 does help in this case.

I think to add some context, here are a couple of images taken with the F4 6" TS Newtonian. This is with a new focuser and a number of mods to give OK results. Make your own judgement. There are also lots of images on line. It should be added that I am no expert and my processing skills still need work....

If you have an HEQ5 it is worth doing the belt modification to improve tracking. You should be able to get below 1” RMS with some fettling. I think mine is typically around 0.7. There is a predictive PEC algorithm within PHD2 in the advanced guiding settings. Change to this and you should see some improvement.

With regards to the 200pds this would be pushing an HEQ5. Although possible, any breeze will ruin your subs.

WRT OAG I am not sure it is needed on a 130. To be honest I have gone back to a guide scope on my RCI at 1600mm because of the issues I had with OAGing and difficulties finding good guide stars.

On 29/03/2022 at 19:09, Richard_ said:

I've been using NINA for a couple of months and up until now I haven't experienced any issues with my meridian flips

I had my first flip failure with NINA the other night. I looked through guide logs and error logs and could find no reason. I put it down to the clocks going forward - but it was a guess. There was no plate solving errors. I also had a similar problem with the autofocus routine running for ages and by the morning the focus was a mile out. Oddly, I am still running the old version of NINA so mine was not a bug in the Beta software.

I was at a loss, so for now I have put it down as a one off glitch. (Interestingly I had two imaging rigs at different FL's out on the same target - one failed one worked fine). Same computer running both scopes (mini PC's)

19 minutes ago, Pitch Black Skies said:

The 150 and 200 will only bring me a bit closer to the target though won't they. What I'm really after is shorter imaging times.

The 200 is around 1000mm focal length which is quite a bit above the 130. Also, in terms of pixel scale, above this you would usually be binning data anyway so there is not a huge amount to gain from the longer FL. However, a 200pds or quattro will be pushing the limits of a HEQ5.

In reality F5 is pretty quick, especially at 650mm FL. F4 would theoretically slightly better but more difficult. There are newtonians produced by Sharpstar that go as fast as F2.8 but they are expensive. They are also not the easiest to work with and would require some modification. I now have an F4 that I will endeavour to work with in the autumn when the nebula's come back out to play. However, with hindsight I should have gone for an F5 or a better scope such as the quattro. But these would have gone an an AZ-EQ6.

Great image. It is the first time I think I have seen the second 'ring' in blue so clearly defined. Benefits of 50+ hours of integration. Excellent.

Personally I would stick with your 130PDS. I have the TS F4 and it took quite a bit of additional expense to get it to give decent images. Firstly, the Baader MPCC I had for my F5 scope was not up to the task of giving good stars to the edge of the sensor. I ending up paying for a Skywatcher F4 aplanatic CC. In addition, the focuser was not really up to the job so I replaced it with a Steeltrack. There were also a number of other changes required to make it an effective imaging scope.

Yes it is quite fast, but for the amount of work needed to get a 'good' scope I would look at something different. The F4 also requires very careful collimation - MUCH tighter than the F5. The other problem I had was awful internal reflections. Although not directly linked to the scope - it was the filters - to use the mono camera would require me to buy a whole new set of filters. I will try it with a DSLR as the reflections may not be an issue.

I don't know what mount you have, but you could look at a 150 or 200mm F5.

I bought a StellaMira F6 90mm ED triplet instead..... but I am nearly £1000 worse off!

33 minutes ago, Jjmorris90 said:

So it’s the same spec ?

Yes as far as I can tell. It is just the original version. 

I'm not sure if there is a hard and fast rule for this but I would say the 3:1:1:1 is a reasonable guide - but experiment. Colour is quite a personal thing, just look at the different processed images there are. No two are the same. Quite often you could also get away with binning colour data to get a better S/N ratio without extending the imaging time. 'All' of the image detail is in the luminance channel.

With regards to the blue channel, it certainly tends to be 'distorted' more but the atmosphere so I would always image this and the luminance as near to the zenith as possible.

As everyone else has stated it certainly looks like and ED80. Does it say anything on the lens?

Edit - I have just found a Sky at Night review of the ED80 and yours is the same. Just an older version.

Sky-Watcher Evostar 80ED Pro review - Telescopes - Reviews - BBC Sky at Night Magazine

I know you have found a diagram with the flattener on the way you have it, but I would try the other way round. On my Stella Mira FF for the 90mm ED I had the knurled part on the wrong end as the threads were the same at both ends. (My writing is the other way round too). Looking at the star shapes the exaggerated coma suggests it might be the wrong way.

The other thing to remember about the Flaming Star is that it is an emission and reflection nebula. The l-enhance will remove a lot of the reflection data.

7 hours ago, Grant93 said:

If it isnt the issue, how would you test / fix the focuser?

I guess one way would be to use a laser collimator to make sure the focuser lines up perfectly with the  centre of the objective lens. You could probably do something similar with a Cheshire and a centre marked piece of paper over the dew shield. I'm not sure with the ZS61 whether the focuser is adjustable though,

Last night I was tinkering with my RC8 and StellaMira ED 90 as both have been giving me a bit of trouble with star shapes. Anyway towards the end of the evening (well my bedtime anyway) I decided to get a few hours on M53 as a comparison between the two scopes.

M53 on its own was images with the RC8 and a modified 600D. In total about 150 subs, each of 2 minutes, native at f8.

The M53 and M5053 was with the SM90 with 1x FF using the 1600mm pro. For some reason the meridian flip failed (might be a clock related issue) so I only got a total of 15x 2 minute of RGB and 40x 2 minute luminance.

There are still problems with the star shapes, but overall the results were not too bad.

As always, critical and non-critical comment welcome. Globulars are not my normal targets so processing was a bit of guesswork!

7 hours ago, alacant said:

Noisy, but am going through a denoise-ruins-so-many-images stage

I have this dilemma with virtually all my images. I try to keep the denoise to a minimum - but I do use it. (Hangs head in shame and stands in the corner......)