Stub Mandrel

On 22/02/2019 at 08:17, Demonperformer said:

Sorry, realise yours is permanent and wasn't trying to hijack the thread (much!), but the process obviously takes a significant amount of time and was wondering if it was still a worthwhile option when all the gear is put back together each session in not necessarily exactly the same relative positions. If PEC is working out of step it would be likely to cause more problems than it solves?

There's a relatively new feature in PHD2 - you need the latest version - called 'predictive PEC' or PPEC. It 'learns' your system's behaviour over the first few cycles and then applies it, and  it constantly refines its model of the PEC. It does appear to work and I use it all the time now.

11 minutes ago, Philip R said:

Here a link to a topic I started/posted last year [2018] about it...

 

Ah, I remember that thread!

Reminds me I have all the key bits for a Herschel Wedge (prism and ND filter) safe in a box. Must get around to making it !

1 minute ago, Philip R said:

Is that glass or safety film? - If glass it still needs to be thoroughly checked for pin-holes before use.

I gave up using my Thousand Oaks 2+ glass filter a few years ago as it is showing a few pin-holes.

Can you not black them?

2 hours ago, Gina said:

I think it should be "We are Borg" ?

They had to start somewhere, and now we know where! ?

1 hour ago, ericleo1 said:

Excellent pics- I looked at the Sywatcher 130p-DF with a view to  buy but what is the cheapest mount you cd use with it? (without going motorised?)

HI Eric an EQ3 will hold it for visual use, but you do need a motor if you are going to attempt photography.

21 hours ago, kirkster501 said:

How do I stop the Saturation of the stars?   A lower exposure?

Easiest way is to auto-select star or choose one that is less bright.

12 hours ago, reezeh said:

I am thinking that I do have to do something to make removal easier and not drop the caps. Maybe a cord like paracord and superglue or hot glue based. Probably will look horrible, but it'll be to do a job that isn't just to look pretty.

You can get little adhesive backed plastic 'dots' strung to elastic loops. They often come free with lens caps on ebay.

28 minutes ago, Grogfish said:

 And if you don’t have to skip around kids toys in the dark then you don’t know what you’re missing out on! 

 

Better than when the SO lets the dog out for its evening ablutions and you don't notice the results...

1 hour ago, JohnSadlerAstro said:

The barlow is an absolute abomination

I was recommended a Revelation Astro ED barlow as giving great performance at modest cost, and it is indeed very good.

Take a look at this excellent thread to give you an idea of what sorts of things you can expect to see. May I suggest you start with the middle 'star' in Orion's sword which is well placed for viewing at the moment. One of the most spectacular sights in the sky the Orion nebula will show as a complex grouping of young stars lighting the swirling dust clouds which they formed from. In my 10" Newtonian I can see plenty of detail as long as the moon isn't too bright and on a moonless night it is quite spectacular.

Last friday at our astronomy group meeting the chair found M94, a galaxy,  in the same scope. A more typical sight this was a circular disc with the hints of a brighter rim and clear central core, despite the moon and persistent thin cloud.

1 hour ago, JeremyS said:

Well, he's certainly a psychiatrist....

Just to prove I'm not totally insane then...

" William "Billy" Sheehan (born March 19, 1953), is an American bassist known for his work with Talas, Steve Vai, David Lee Roth, Mr. Big, Niacin, and The Winery Dogs. "

13 minutes ago, JeremyS said:

Cor, I thought he was just a bass player!

2 hours ago, rotatux said:

but I can see the diffraction pattern of a closed diaphragm on bright stars... so are you sure it was wide open

Good point! Perhaps it wasn't?

I have used it wide open.

It does suffer a bit of CA with blue stars getting small haloes, but easy to process out.

Should have had about £3 worth of microphone inserts inside... looks like the sewing machine  ran out of cotton! (They were only wireless in the sense of no wires...)

39 minutes ago, rotatux said:

My copy of the 200 (same "bokeh monster" variant as yours) is very soft at F/4, I must close nearly at F/5.6 to get decently shaped stars (esp. on borders and corners). This is why I ended getting another 200 (Olympus OM) which is fine wide open at F/4 (though it suffers another aberration).

About 135mm I've got many, 2 M42/Pentacon F/2.8 (long and short) that are both good at F/4 (the long variant is a bit better), and 2 F/3.5 from Minolta and Olympus which I barely tested but need to be closed at F/5.6 (Minolta much better). Having to close is normal I think, the shortest the focal the bigger aberrations need to be corrected by closing; Only long focals would be kept wide open, at 200/4 you can find many good ones (don't know at 200/3.5), at 135 I didn't encounter any yet (but maybe some F/2.8 from Minolta, Takumar or Pentax) -- though if you have budget there's the Samyang 135/2 which is a wonder from what I have read everywhere.

Phew! That's a collection.

Have you tried a Zeiss? - it was they that invented the Sonnar configuration. This is the  135 f 3.5 wide open:

4 hours ago, alexbb said:

4 hours ago, RayD said:

or the OVL one (with the nose cone removed and screwed to the draw tube)

Hah! Did I miss that?

I did!

Wow what a great selection of images!

It is with great trepidation I offer my own!

Garnet nebula and elephant's trunk.

Comet Wirtanen

Andromeda

PeliNAN

M27

I find my Helios 44M 9which is 58mm fl for the confused out there...) standard lens has pretty poor stars in the corners, a big disappointment as it took great terrestrial pics.

Some of my other pentax screw lenses have been better.

9 hours ago, Minhlead said:

wow, really? Thanks! I think I'll give it a try

Just to be sure, I mean using it on after stacking your data but you need to experiment with the best point in your processing workflow to use it.

6 hours ago, Craney said:

... and there seems to be a pair of eyes admiring the set-up from down the garden as well !!!!!.... yikes.

It's a Jawa planning to recycle your robotic scope ?

45 minutes ago, bobmoss said:

Unfortunately I live near-ish to the main town of Portree

Well that's a phrase you don't hear very often...

2 hours ago, Minhlead said:

Looks like the denoise algorithm of Astra is somewhat better than lightroom but you still lose detail when do the denoising in post so I'm looking to optimize my stacking workflow. But thanks for the suggestion

Bear in mind that I did that on a screen grab of a jpg, you can do it on your 16 or 32 bit uncompressed original data.

4 hours ago, Saganite said:

Skye is class 1 Bortle.

Skye has its own challenges. Right at the start of getting into this hobby I tried to get some photos with the limited long exposure on my bridge camera. Parked up somewhere on the coat road I didn't do very well, and when I started hearing large animals breathing loudly and moving around on the rocks nearby (I guess they were seals) it did get more than a bit spooky...

9 hours ago, bobmoss said:

Interesting, thanks. I guess you take a reading and then decide if its worth getting a scope out?

On Skye?

I would suggest getting a scope out (a) it's actually going to get dark (b) it isn't cloudy and (c) the sheep are able to remain upright.

?

1 hour ago, Geoff Barnes said:

We live out in the sticks a bit here with dirt roads, so dust is a very big problem in the summer moths. 

My open collapsible Dob is a sitting duck for contamination from dust not to mention swarms of Australias finest bugs, so it seemed appropriate to order some protection in the form of an Astrozap shroud.....

Have you tried moth balls?