Ags

Not sure I can get closer with a Cheshire. Tonight the stars!

The bigger the star, the higher the pressure in the core.

Tried out my FLO Premium Cheshire Collimator.

Before:

After:

Aligning the primary has pushed the secondary out a bit again, I'll do another iteration tonight. So far it looks like the focusser is reasonably aligned...

Had some patchy clear skies after midnight, enough for a star test. I'll need to work on the collimation clearly. 

My pet RC "Archie" arrived today. First impressions are favorable, it seems solidly and simply made. The focusser looks quite reasonable, although I know it may be one of the most replaced focussers in the hobby... The dust cap is a bit flimsy, it looks more at home on top of a yoghurt pot! Being such a back-heavy scope, they could have ran the dovetail all the way to the back of the tube. It looks like I can put a dovetail on the other side, which would be a useful carry handle.

Not a fan of collimating the secondary with an allen key over an exposed primary mirror!

From the fractured polystyrene, it seems it had a few bumps on the way to me. Hopefully I can check the collimation properly over the weekend, but a rough "hall of mirrors" check looking down the tube suggests there's nothing extremely wrong with the alignment.

Yes it is an RC6, 154mm f9. It is primarily for imaging but will see how it goes visually too.

Yummy!

Maybe this one?

Creality 3D Ender 3 V3 SE - Kenmerken - Tweakers

I thought about it but decided straight ones should give a little less total diffraction. It's not like I'll be seeing any star spikes  Also, I could have tried 3 vanes instead of 4...

This is 50% linear central obstruction. If this shows any promise I might try 45% or 40% too. I guess there's a balance between contrast loss from the central obstruction and any gain from a more collimated beam.

I am on the verge of buying a printer now - a two week wait for a print is annoying and the delivery costs are painful. And I think some/most designs will need some iterative development.

I also thought nylon might be a better choice as the obstruction is supported by relatively thin vanes.

I looked at the heat characteristics and selected Carbon Fiber FDM Nylon as the cheapest and most heat resistant option.

My first print arrived today.

It is a counterintuitive aperture mask for a SolarScout 60. One of the criticisms of this scope is that at f15 it is far too fast for its built in Quark. Only the middle 30 mm of the aperture would be on band. But what if Daystar cleverly shifted the SS60 Quark so it's optimised for the light coming in at the f18 angle? Then most of the aperture except for the middle would be on band. This mask tests that theory.

The mask was too small to fit on the scope (of course) but after a little sandpaper it just about fits. 

@vlaiv previously tried to explain why this mask idea wouldn't work, but it seems like an easy experiment to try, so we'll see on the next sunny day 😀

The first rule of cleaning mirrors is Don't Clean the Mirror  

I have some trepidations about the collimation - I got it at a nice discount as a customer return from FLO so perhaps the previous owner hit a collimation wall?

Lots of RC goodness there! Both images are good but I find the new version more aesthetically pleasing, somewhat more understated and Ha more blended in.

I was imaging M101 with my ZS66, reduced for f4.3, I managed only an hour and a half before the battery died, which more or less coincided with the skies turning excellent! Looking at the background noise from the Amsterdam light pollution, I think I will need another 8 hours before I can start to separate the outer regions of the galaxy from the noise. But long before then my RC6 will have arrived and the ZS66 will be forgotten about for a few months!

It should arrive on Monday! I hope this scope will also work well for spectroscopy - I have a grating flying over with a relative later in the spring.

Congrats on 5k posts!

Polar aligning... I still can't do it after all these years, but my AsiAir can. I follow its instructions without question or understanding. The computer overlord issues commands and the lowly humans turns the gears. Then it tells me "well done" after having done little more than screw a cap on a toothpaste tube 😀

Just now, Adreneline said:

You probably don't want to hear this but I found I couldn't get a satisfactory collimation with the stock focuser unit

No I don't want to hear that! But I can get the GSO tilt adjuster which should resolve the issue. Also I am not hanging anything heavy off the focuser - just an uncooled camera, a reducer and no filter wheel etc.

13 minutes ago, Adreneline said:

I now regret selling as the images it produced when used with an ASI294MC (also sold  ) were very good indeed.

Say more things like this

I have been thinking about a scope acquisition for my HEM15 mount, as a replacement for my C6. I thought about a planetary specialist  scope like a Classical Cassegrain 8", or a small photo newt at the other end of the scale, but in the end I went for a Ritchey Chretien 6"... It seems like the ideal scope to go after galaxies and planetary nebulae. I only have moderately small chip (ASI485) so I haven't purchased a tilt adjuster for the focuser - I will probably add that later. I know RC collimation is a famously fiddly thing. I hope to get close enough with a cheshire and finish the process with star testing. I may end up buying more collimation mcguffins before I'm through!

I thought I would pick up the RC6 for galaxy season. I'm curious to see if the scope produces better stars than the C6 did, and if the scope is less vulnerable to wind than the C6 and it's obligatory dew shield.

Interestingly, the scope gives one degree FOV with my ES60 20 mm eyepiece, so I hope it will also work a DSO scope. Not too sure it will work on planets, but I hear RCs perform OK on the Moon at least.

Yes, thinking a lot about buying a printer. Maybe next year after we move house.

I think the 10" classical Cassegrain would look great in an observatory.

6 minutes ago, Zermelo said:

make sure it hasn't been activated on too many other phones

That sounds like borderline illegal product design! You can't factory reset it? After 4 phones it is a dead parrot? I am going to get the EU to ban this ludicrous e-waste (after I have bought one).

Well, I'm sure the optics are fine, but I have my doubts about the focuser and the mount, but most importantly there is a StarSense module attached to the Celestron AZ70. Is StarSense really that great?

Welcome back Louise! It might not be what you are looking for exactly, but I recently invested in an ultra portable setup based on the HEM15 and AsiAir Mini. Both are really impressive and the Air would be my recommendation for armchair imaging. Coupled with a small scope and guidescope and a lightweight tripod, the setup is an easy lift. The Air can do all sky polar aligning so you may not need Polaris.

1 hour ago, michael.h.f.wilkinson said:

This is why software for faint object detection we are developing at the University of Groningen relies on statistics to ensure there is enough evidence for the presence of something that cannot be explained as a random fluctuation caused by noise.

Interesting.... isn't that however the same as saying "we are developing a new stacking algorithm"?