osbourne one-nil

Where did you find these...or is that your secret?!

Are you still happy with your FMA230? Your Astrobin photos look great. 

I ask because I placed an order for one yesterday but then asked the store to hold on until Monday in case the ACL200 was vastly better. They seem fairly different types of lenses and the 230mm focal length of the FMA230 suits me better in framing-terms, so I think I made the right choice.

I just want a nice flat field with no hassle and I don't really crave the wider field of view the ACL200 would give me, although I could always crop if it was a lot better!

Tempting - I currently image with a Vixen doublet and flattener, and it's absolutely fine (rather good actually). I might try one of these and see if I prefer its simplicity compared to the similar focal lengthed R200SS I have. I know I'd be sacrificing speed and aperture, but I do find imaging with a Newt pretty stressful!

Did I post these before? 

I had a SD81S but I had a tax bill to pay so, being me, spent some of that money on a new telescope instead; the SD81SII. I was wanting to get rid of the diffraction spikes caused by the foil spacers, and sure enough, they're now gone. The original SD81S went shortly afterwards too. 

Because I had the dedicated flattener and reducer for the scope, and because that would also work on the SD103S as well, I keep toying with the idea of replacing my R200SS with the 103, and be done with collimation (at the expense of speed and aperture, of course). However, now the Stellalyra 127 doublet is out, I could save a ton of money.,,,

On 01/12/2022 at 09:41, 900SL said:

Looking forward to seeing your results. I have the IDAS NBZ dual band Ha Oiii OSC filter and am thinking of getting the Askar Oiii Sii as well. I haven't had great experiences with Askar QA on a scope so looking forward to any third party reviews 

Did you ever do this? I keep wondering about how it would work...along with wondering if I could be bothered swapping filters, or even have enough imaging time to make it viable...but as a starting point, I wonder if it works in theory?

59 minutes ago, Adam J said:

 Time taken thinking about this stuff is imaging time lost. 

Time living in Cumbria is imaging time lost!

58 minutes ago, Clarkey said:

Definitely.  I have the Rising Cam version of the 2600 and use it at a number of FL's. Yes, there is a theoretical sweet spot, but there are a lot of other things that will impact the quality of your images long before the pixel scale starts to come into play.

Excellent - thanks. I was in Penrith last night....how many lights does Gilwilly have these days?!

23 hours ago, Adam J said:

 your over thinking it...just get the camera. 

Adam

I've already got it! I was just having a think about my setup. I'll stick with what I have!

On 24/02/2023 at 11:16, Adam J said:

If you can get hold of a spot diagram then spot size is also an important factor in understanding resolution. Of the spot size is significantly larger than the pixels then you won't achieve the theoretical resolution even in perfect seeing.  The other thing with the CCD suitability guide is that it makes no account of OSC sampling due to the Bayer matrix and so only really works at all for mono cameras. 

Adam

This is where my brain starts to melt. Actually, my brain does that way before this stage. 

Here's the best spot diagram I can find, and I have both the Extender PH (which is the top one) and the Coma Corrector 3 (3rd one down) and I shoot with an APS-C sized sensor. Hmmmmm!

Thanks all - I'm finding it difficult to ask the right question! 

I shot M81 a week or so ago, with everything the same (number of subs, gain, total integration time etc) other than the telescopes. One was shot with my 81mm f/7.7 apo and one with my 8" f/4 Newtonian. Once the images were scaled to match, and I did this both ways (scaled the refractor image up and compared and scaled the Newt's image down and compared), there was really not a lot in it. Ok, they were taken on different nights, but conditions were pretty similar. 

I'm surprised and far slower, far smaller refractor can even get close to a much faster and much larger Newtonian. This is what led me to ponder if to get any benefit from the Newt, I'd need larger pixels....or finally get my head around binning. The other option is, of course, to just have one scope, never have to fiddle on with swapping things over and collimation and have an easy life!

Does anyone know what the "SS" stands for....and I don't mean in the political sense. 

I've rephrased my original question into something more specific  - what would you say the sweet spot is for an ASI2600MC Pro camera, in terms of scope? Running the CCD suitability guide in Astronomy.Tools, it would look to be something around the 500mm focal length mark, which results in around a 1.5" per pixel. Is that the sort of thinking behind this?

If so, the best corrected/largest aperture resulting in that "/pixel ratio would be something like the Esprit 100. Being a triplet, would that give me a noticeably crisper image than my SD81 doublet? Is the aperture and 800mm focal length of my R200SS being wasted by the "limitation" of my camera's small pixels?

Basically, what's the best combination, assuming the camera is the starting point on this occasion? 

You deserve even more credit then as you won’t of been taut it proper. 

I've got an Ecoflow Rover Pro and it's great because it charges SO quickly; from drained to full in around 2 hours the other night and then it powered my rig; (you know what mount I have!) 2600MC Pro and two dew heaters, from 9pm to 5am, with the dew heaters left on until 9am, with 65% remaining. 

I still tend to use mains power when I can because I know all batteries have a limited number of charge cycles, but one of the cheap amazon AC/DC converters I had been using went pop the other night and it really really hurt!

By the way, I love how two Finns converse in English far above the level spoken by my immediate neighbours. 

Oh yeah - I've dug out the invoice and it does seem I bought a few other things too. Argh. 

The price from Bresser is inclusive of everything so I'm not sure how they do that!

I'd much prefer a UK supplier held stock of Vixen stuff, of course, but I've bought a bit via Bresser recently and it's all come within a week and I had one warranty issue, regarding a broken bolt, and it was dealt with really quickly. It's fine...tracking is weird as the items disappear for a few days, but then they suddenly reappear and arrive the next day. 

If you're after Vixen, I'd still go for it. 

I'm probably way too late here, but I image with the SD81S (essentially the same optics) and find it really nice. It's so lightweight it puts absolutely no strain on the mount. Initially I used the Vixen reducer with it as I was worried that f/7.7 was too slow, but more recently I've been using it with just the flattener at its native focal length and have been really happy with the results. There are some spikes on the brighter stars because of the spacers around the edge, but I live with them as they're part of the scope, so perfectly honest!

You wouldn't need any of those extra items but if your DSLR is full frame you'd probably want the flattener, which screws into the drawtube nicely. You could try without, of course. You don't have to do anything!

Vixen stuff is lightweight, robust, and lovely. I wouldn't hesitate!

Now, I asked someone who works for the BBC in outside broadcast about cold-weather cables, and ended up getting this https://www.canford.co.uk/Products/46-9315_CANFORD-CABLE-RJ45-RJ45-CAT5E-F-1m-Green

It's floppier than a Mancunian's haircut from the 90s, and it's been out in many sub -10 nights.  

Yeah, I'll do that. Good idea!

If I could justify anything, I would!!

I've noticed a chip on the paintwork of my SD81. Obviously this is upsetting me massively; does anyone know a matching colour for VIxen paintwork? I asked Vixen directly once, and they said they didn't have an RAL code for it. I bet they do really!

I'll have a go with this shot which comprises just 30 x 30" of imaging, using my R200SS and an ASI533MC Pro camera. Whenever I wonder about matching the 800mm focal length with a slower refractor, I look at this image and think maybe I'll stay with the Newt!

On 18/09/2022 at 15:43, Pixies said:

Up here in Edinburgh, the latitude is about 56° North. That's touch-and-go with the Vixen AP:

I assume that as the lower end of the RA body comes down, the adjuster bolt screws in enough to miss it. But it's pretty close!

I'm at 54.5 and even I have to orientate the bolt thing correctly. It's fine if the end cap comes off, but it is a bit of an oversight I think.  The mount itself though is lovely!

Hi Pete - sorry, missed this. I've been looking for a diagram like that but have never found it; where did you find that?!

As for the 63.5mm…that came directly from Vixen!

Thanks both - even Ian (I do have a flattener on my refractor so the knowledge will still come in useful!)

12 hours ago, RolandKol said:

If you use autofocuser and NINA, it has nice aberration inspector,

It will run autofocus and will calculate the aprox distance to move sensor to/from Coma Corrector.

That sounds very clever. I've never used nina but there are plenty of awful nights when I can get to grips with it and perhaps there might even be a clear night when I could try it out. 

This certainly discourages me from rushing into a larger sensor camera....and emphasises the benefits of those lovely Petzvals!