Ratlet

I might get 2.  I'm wondering if they'll 'handle' 8kg of lifting force could I make use of my obsolete 1kg ioptron counterweight for a weight to balance my dob.

39 minutes ago, vlaiv said:

I started a build of one - but I'm mid way through it at the moment. Not sure when I'll put some effort into finishing it though.

Need to redo 12V power supply. It's there to power fan (I planned to do hepa filter + activated charcoal to recirculate air inside of enclosure) and lighting and to provide additional power for BananaPI for Klipper.

I'm not overly happy with wiring and switches (I managed to mess up wiring so only output for BananaPI is working at the moment). I'll split it into two units. Main unit that provides 12V for lot and then "breakout" box with indicator leds and switches for fan and led lighting.

 

I do like the activated charcoal recirculation idea.  I used it once for another hobby...

They've been keeping quiet on the REALLY important new release:

https://www.firstlightoptics.com/adapters/astro-essentials-magnetic-handle.html

Better be quick.  They've only got 96 and knowing the forum, some people are going to end up with scopes that look like hedgehogs.

Looks good and like you've said you printed so the planes aren't in line with the force.

PLA isn't the ideal material as it can deform easily with heat or continuous load, but petg or asa might be a better choice.  Not massively familiar with different materials but an enclosure is pretty useful for petg and others.  The other advantage is you can fit an extractor easily enough to an enclosure.  IKEA lack tables make an excellent choice for a cheap frame.  I've had some stinky pla (esun Matt black) which I couldn't stand being in the room with whilst printing.  Smelled like burning tyres.  Bathroom extractor to the back of the enclosure and a vent would nuke that though 

Cheers guys.  I need to have a play around with my setup once the clouds clear and figure out the best bet.

I'm going to second what @bosun21 has said.  It's the bulk that's the issue.  Sack barrow (with an extendable toe) works wonders though.  I keep mine up the shed under telegizmos cover with a dehumidifier bag that can be recharged in the microwave and observe from my back garden.

Because of this I can be setup and going quicker with my 10" dob that I could with my 5" Newtonian on an azgti.

I got the Stellalyra 10".  I'd consider getting a telrad or Rigel quickfinder.  Much easier than a finderscope.  With the Stellalyra 10" you get a 30mm eyepiece which gives a wide enough fov to use as a finder eyepiece once you get to a bright star.  I only use my finder scope to make sure I'm really centred at high power.

Personally the number one thing to get is setting circles.  Either digital or manual (I use manual).  It's like what goto should be.  Lots of posts on how to set it up.

Starsense does the same thing, but a bit better apparently.

Variable polarising filter is the way to go for the moon.  Personally I'm not a fan of Barlows, but if you go down that route and get a VPF, you can unscrew the two bits of the vpf and put one bit on the Barlow and one bit on the lens you are using and you can adjust the brightness of the image by rotating the eyepiece in the Barlow.

Does anyone know if it is possible to replace the compression ring on the Stellalyra 10" dobsonian with a baader click lock and if so which one would fit?  I've heard good things about the click lock and it might be a reasonable upgrade.

I tried unscrewing the one that is on it it but it seems pretty well on there.  Not sure if it is thread locked or more permanently attached.

57 minutes ago, RobertI said:

A nice 32mm Plossl for my C8, as recommended by @bomberbaz (thank you) to help me with my nemesis, the Crescent nebula. 
 

My 32mm plossl is still one of my favourite eyepieces.  A great choice.

Cheers guys,

I'll keep an eye out for the book, hopefully they will reprint it or one will come up second hand.

telescope-optics.net could do with coming in a print format.  I struggle with meaty reading when it is through a screen for some reason.  I suspect that there is probably a minimum understanding required that will make it more intuitive.

Do you guys have any suggestions for good reading materials on telescope optics?  This is all fascinating.

Dang, they look nice.

2" Filter boxes done now:

https://www.printables.com/model/471145-standardised-2-filter-holders-boxes

1/4 in unc I think.

4 minutes ago, saac said:

Add to that aviation too. When you fly to your holiday destination the fuel load is calculated and recorded in lbs. Err,  lbs that's Pounds for the youngsters  (2.05 lbs for every Kg). Air Speed of course is recorded in Kts  and not m/s (kts  = knots or nautical miles per hour).

Jim 

2.204lb per kg.  It's a number etched in my soul.  Although for most of the calcs I need to use it for I find 2ish works.  

Not just the oldies and yanks.  The Oilfield loves it's archaic units.  bbls and feet and inches and gallons.  Decimal feet and inches though.  pounds per barrel and pounds per gallon.  Europe has moved on to metric, but the rest of the worls persists.  You get some crazy units when the two clash.  Like length measured in meters width in inches and volume in m3.  Let's not forget that an American gallon is different from a British gallon.  Seen that cause problems more than once.

My personal favourite is when you are measuring fluid consumption whilst drilling.  volume is measured in m3, length in meters so your consumption works out m3/m or m2.  Fun fact, major oil companies don't like you writing fluid consumption as an area, even if it is technically correct.

14 hours ago, PeterC65 said:

Seeing the Horsehead still makes me smile when I do EEVA. As a child it was the first DSO I came to know about and I've always wanted to see it. Visually for me there is no sign of it, nor of the Flame Nebula for that matter, but using EEVA the whole group of objects just pops out. I love trying to get a better view on the night, and with a little post process tweaking I've managed to get some nice images. Here's my best attempt so far.

I like what you've managed to achieve with a 135mm lens. I have just brought a bracket to attach my DSLR with its telephoto lens to my scope mount and am hoping for a similar widefield view of Orion come the Winter.

 

 

 

Thanks very much.  That's a cracking image of the horsehead.

The only thing that stops me doing pure EAA is that I am really enjoying visual and so far have tried to milk every available minute at the scope.  That being said I usually don't spend too long on a target for my images and don't have the patience to do lots of processing.  I usually load up NINA in at the start of the session witha list of targets and then leave it doing it's thing.  Quick stack, stretch and noise removal and call it good.  I think I might lean more into shorter duration and more targets.  Or even try nights of pure EAA.  My work schedule means I don't really get observing time when the moon isn't some flavour of full and I'd probablyget more out of DSO by doing EAA.

This has been really educational.  I didn't know eyepieces could have different magnifications across the field.

Going to have to do some reading (cause with the weather for the foreseeable, I'm not going to get much observing done).

Cheers guys 

1 hour ago, Louis D said:

Well, you'd have to refocus for the edge of field to see if the edge sharpness returns to be able to definitely assign the blurriness to field curvature.

My Pentax XL 14mm has near perfect edge correction, but it also has significant field curvature.  When I bought it in my early 30s, it looked sharp edge to edge.  Now in my late 50s, I have to refocus it to see that sharp edge again.

If when refocused for the edge it is still unsharp out there, you're probably dealing with astigmatism issues.  This assumes you've got a coma corrector in your 130PDS.  Without one, you'd be seeing quite a bit of coma as well.

Setup a pinhole light with some foil and a flashlight (torch) in a darkened room for more advanced testing.  Getting the pinhole small and round enough is the problem in my experience with this approach.  Alternatively at night, put a fairly bright star in the center and slew it to the edge.  See if it goes blurry.  Refocus it to see if gets sharp.  Look at the shape of the star on either side of best focus.  If it alternates between radial and tangential lines on either side of best focus, that's classic astigmatism.  If it simply looks comet like, pointing to the center, that's classic coma.  It can look like a combination of those two.  Commonly, chromatic aberration is also thrown in for good measure making pretty rainbows out of the star.

Might have test this out with an artificial star.  I'm quite good at making them now as I had to do a bit of trouble shooting on a couple Tair 3 lenses and eventually identified the issues as being astigmatism in one and being cleaned and assembled by an idiot (I put the front element in backwards) in the other.  Did an awful lot of testing with the hole in tinfoil.

48 minutes ago, Don Pensack said:

If the flagpole is a cylinder (likely), then there is some angular magnification distortion in your images.

The edge looks more magnified in both eyepieces.

I suspect this is in you camera as AMD in eyepieces is almost always the reverse--the edge has a lower magnification.

 

Your images also reveal the edge vignetting in the 16mm (often reported), and a slight brightening of the edge n the 17.5mm (not reported).

Also, the 17.5mm has the common edge of field CA--the blue ring, as in most complex negative/positive designs.

The 16mm appears to have none--it could simply be the vignetting that reduces its visibility.

I think the edge brightening might be an artifact of the image rather than the lens.  It was a struggle to get the camera far enough from the eyepiece to not get blackouts.  The think there is a slight amount of tilt as the phone holder was hanging on the edge of the eyepiece and it was threatening to black out.  You can kind of see the crescent shape of darkness.

Oddly the flagpole might not be a cylinder.  About 1/3 of the way in from the edge you can see a join from the larger lower section.  I didn't notice that till you mentioned it.  You've got a good eye!

Really appreciate @Don Pensack and @Louis D feedback and comments.  Really helping me to understand eyepieces.

8 minutes ago, cajen2 said:

Wouldn't mind betting the Morph will wipe the floor with the OVL, even though the latter is an extremely good VFM EP.

I added a link to my ongoing saga in wide angle eyepieces.  I'm still new to the whole imaging through a lens thing and the images were taken in the day, but I would say it does.  The OVL does a good job, but I found the distortion a bit too distracting sometimes, especially when trying to sketch.  On a lot of objects it's not an issue, but there were a couple where it gave me a sad.

So the 17.5mm Morpheus turned up.  Nice bit of kit.  I've got clouds till the end of time so decided to do a completely unscientific comparison between it and the OVL 16mm and setup the 130PDS and used the moveshootmove camera holder.  I suspect I still need to dial everything in for using the camera holder, but it works well.  Getting a good view on the Morpheus was a bit of a challenge, probably due to the eyerelief and the fact that my Pixel 6 has protrouding cameras which removes some of the room for adjustment.  In both cases I tried to get the best possible focus on the flag pole.  Happy with the performance of the camera itself.

Here we can see the image from the Morpheus which looks pretty well in focus to the edge.

And here we can see the OVL.  To my eyes the OVL focus goes pretty wonky on the way out of the field.

Now the stupid question, is this what we mean when we talk about flatfield?

A typically quick delivery from FLO.

I swear my wife's engagement ring came in a less fancy box.

Couldn't resist giving it a try and compare against the OVL 16mm.  Also took the opportunity to try out the MoveshootMove mobile phone holder.  Pretty minimal flex in the setup on the scope and surprisingly not that difficult to setup.

Going to have to look into getting a new setup for the eyepieces.  Between them and the various other gubbins I need to take out on a night I think a small camera backpack is on the cards.

Edit:  I'm removed the miages through the eyepiece and put them here:

@LaurenceT did you save any of the images you got?  I'd be interested to see what you are getting with your setup.

13 hours ago, bosun21 said:

I agree with you about EEVA and I am seriously considering starting again. I basically have everything I need apart from the camera. What do you think about a dual band filter for EEVA?

Not tried true EAA yet, however I picked up the SV220 filter from SVBONY which is a 7nm dual band.  I was intending on trying it with astrophotgraphy, however my mount went bonkers during the session and I ended up only getting 10 minutes of data (10x 1 minute subs)  on the horsehead with a 135mm F3.5 (Stopped to F4 or F5.6, can't remember).  This would have been gathered during with the moon 3/4 illuminated. 

I've attached a stacked image from siril with only an autostretch and rough colour calibration applied.