Clarkey

If it's something big, I can't afford it🤣

I am not exactly sure why your set up is behaving as it is, but the backlash graph is very odd. Initially the backlash is showing very little, then it stops responding. Normally the 'measured' line runs parallel with the 'ideal' once the backlash has been removed. This suggests the mount is no longer responding to the outputs from PHD2 - but I don't know why.

Personally, on a relatively under-sampled image scale, I would increase your dithering to a larger figure. It is possible PHD2 is struggling to detect the small movements? Alternately, you could try without dithering. (I tried with my colour camera and it had too many hot pixels so I stuck with it. Some you might not need to).

1 minute ago, RJC said:

How does the portability compare between say the Evostar 102 and one of these 8" Dobsonians?

Welcome to SGL.

One issue with the Dobs is that they are not that portable. Certainly, a refractor is easier to move. As with all these things there is a compromise between size, weight, cost, focal length....... If you want portability and you are looking at planet and the moon, a Mak or smaller SCT may be another option to consider. Just as a slight aside, do consider used equipment. Most astro gear is well looked after and there are often good deals to be had on here (once you have enough posts to access the classified section) and Astro Buy and Sell UK.

I would avoid the beaches for observing as there is going to be a lot of moisture in the air, along with a lot of air turbulence between the sea and land mass. Also, salt and telescopes do not go well together!

7 hours ago, mackiedlm said:

It has indded been a bad year for AP. But some great images produced above.

While complaining about lack of clear nights on another forum, I was contacted by a guy in Colorado offering to colab with me to help me finish a project. This was the result.

 

 

That is a stunning image. Impressive indeed.

On 17/12/2023 at 13:07, old_eyes said:

Pleased with this one, but suggestions for improvements gratefully received.

Great image in the nebula. Personally, I would put half an hour into RGB for the stars. I find this really helps with NB images.

Not sure if it related, but I have had a few issues with registration of Roboscopes data (P3 here). I do wonder if some of it is due to the very high humidity recently, causing some fat stars on certain nights. Probably unrelated but blinking through some of images has really shown the variation.

As said by a few people, looks like a combination of balance and seeing.

Just think yourself lucky that you have a Mesu. You should try a SkyWatcher mount. Random movements everywhere!

On 12/12/2023 at 18:30, paul mc c said:

"We choose to process......not because it is easy...we choose to process because it is hard"

Showing your age🤣

Much as that is impressive, with all the new tools we will get to the point of loading subs and let the software (AI) process it for you. Yes, I use PI and BXT, but there is an element of guilt. Part of the challenge of AP is good data collection and processing. Maybe it is getting too easy?

Although not technically my best, I really like this one. The embryo nebula NGC1333.

Flats should still work. I use a filter on the very front of my FMA180 and it works fine.

FWIW I had a similar donut on my first use of a new Risingcam IMX571. I assumed that it was an issue with the camera - I was wrong. It was caused by dew on the sensor. I gotta new heater for the camera and it's been fine ever since. Just a thought....

The 115mm Altair triplet is only £1300 and well proven. Not sure how much difference the extra 5mm will make.

I submitted a version of the NAN a few weeks ago and it was suggested it was a little 'monotone', which was probably true. Anyway, having been working on my use of Pixinsight, I have now re-processed and produced a new, more colourful result. First image is the original, second the 'updated' version. Imaged using the FMA180 and RisingCam IMX571 with the L-extreme. I'm still not sure which I prefer.....

From experience, I would suggest that the video method above is fundamentally flawed. This assumes that the primary mirror is perfectly aligned with the focuser - which in most cases on these 'budget' RC's is not the case. I tried this method once on my RC and it was awful. Personally, I would suggest you align the secondary as described in the video (step 1), but do NOT use a laser to try and align the primary. Providing your collimation is not too far off, you can use a star test to get the primary right. You can do this following this method:

A Procedure for Collimating Ritchey-Chrétien and Other Cassegrain Telescopes (deepskyinstruments.com)

This is the most reliable method I have used. You can get it pretty close using the outer ring (as shown in the video at the beginning of step 2, before the laser). This works on the RC6 (but not on the RC8).

I have the 115mm Starwave which is FPL51. I have found the correction excellent and use it for visual and AP. I would therefore assume the Wave would be better. I am picky about CA and I am happy with the cheaper version, so logic says the Wave should be superb.

FWIW, I have purchased a few things from AA and they have been very helpful. So no complaints from me.

On 20/11/2023 at 21:09, Quetzalcoatl72 said:

It's never been collimated and my NEQ6 struggles with this load as 3minutes is the max it can go guided and even then you've got eggy star

Collimation is tricky, but not too hard. You certainly don't need vast amounts of expensive kit. For mine I get the secondary aligned using a Reego (but you can do it with a Cheshire) then get the primary perfect using a star test. I found this to be the best guide:

A Procedure for Collimating Ritchey-Chrétien and Other Cassegrain Telescopes (deepskyinstruments.com)

With regards to the NEQ6 struggling, it should easily manage the RC8. Maybe the mount needs a bit of fettling? I have imaged with my RC8 on an HEQ5 (albeit it was at the limit) and it was OK.

9 hours ago, Bluesboystig said:

I'm sure there's plenty I can do better in processing.

Processing is probably 75% of imaging. I have been imaging for 3 years and still consider myself a novice. Not only is it a learning curve, but the software is improving rapidly too. Give it a couple of years and we will just plug in the images and AI will do it all for us🤣😭

Have you downloaded the image and looked at the histogram on a PC? Does it give the same result? It does not look genuine so might just be a quirk of the Asiair.

I'm probably being a little pessimistic in terms of data needs, but I would rather have too much space than not enough. The site expects to get around 200 clear nights per year - which is a lot of data. I generally double what I need to give me a mirror copy. As a syndicate member I have no say on what other people image, or the sub lengths - however, the maximum for the scope would be 180 secs.

4 hours ago, ONIKKINEN said:

Time to invest in new drives i would say, 4TB SSDs are really not too expensive these days

I already have two SSDs and an additional HDD in the PC giving me 8Tb total. I also have 2 associated external drives to back these up. I use the SSDs for the OS, programs and one is a 'working area'. The rest is just storage. I probably need a couple more 8Tb drives to keep enough space for a couple of years.

I think @vlaiv and @Fegato, you are sort of telling me what I already knew. I was rather hoping I had missed something obvious and there was a way round saving all my subs. I know I am probably going to get at least double the amount of data I have had over the last 3 years - that is a lot of disk space. I even avoided full frame sensors to keep the size down. I will potentially have the option of saving binned files which will help.

The idea of grouping exposures might be a good one. I'll have a thing about the best way to automate the process.

I have recently started to image at a remote site and the amount of data I will be getting is going to be a lot more than I get currently. (Hooray - clear sky). However, the negative of this is that I will have a lot more data to process and store.

To reduce the total amount of data, I could limit the flats / bias / darks etc. by saving the master frames only. However, currently I keep all of the original light frames. My question is this; when I have multiple data sets over a number of nights (or scopes), will I see any difference integrating the master light frames only over re-integrating all of the frames together? If there is no difference, I would only need to keep the masters, drastically reducing the overall amount of data stored.

I realise that data storage is relatively cheap, but there is also the backing-up and management of all the data which adds to the time / cost.

What is the general consensus? Do I need to keep everything, or just the master frames?

15 minutes ago, Nigella Bryant said:

People use torches to walk up the road here

I need a visor to reduce the glare🤣

Great image and processing. Much as I love these subtle dusty images, I always seem to struggle to get the dust detail. (Not sure whether it is completely linked to my B6 skies). You have certainly nailed it on this one.

What I do want to know - where did the clear nights come from?

The ZWO 120 mini is only USB2 so you will not get very high transfer rates. (Plenty for guiding though). The main thing is to make sure any cables and ports are backwards compatible to USB 2.0.

I know nothing about Macs - so this is my opinion for Windows PC only. (I am no expert so hopefully someone more knowledgeable will come along)

Despite the PI website suggesting you need the greatest PC in the world, a reasonably decent PC will work. Obviously better ones will be quicker. I would say you definitely want and SSD for your working area of at least 1Tb. Use a standard drive for storage - but for PI you will need lots of it. I had 32Gb of Ram on my PC, which I upgraded to 64Gb - but this made no real difference in performance. I don't think PI uses the graphic cards to help in the processing, so spend the money on the main processor to give the best performance. (Obviously this may change in future releases). FWIW I use a Rysen 5600X which works fine, but a quicker processor with more cores would be better. (PI seems to run processes on a core-by-core basis). The other worthwhile investment is a decent monitor. I have a 27" 2560 x 1440, which I would say is the minimum specification you really want.

I am no expert in PC's, but I built mine on line from PC Specialist about 18 months ago. I did a bit of research to get the best bang for my buck, but with hindsight a slightly better processer would have helped. However, at the time I was using other software that did take advantage of the graphics card capability, so the build was a compromise - largely on cost vs performance.

So, in summary I would say 32+ Gb RAM, large SSD working area, plenty of drive space (or external) and the best multi core processor you can.