markse68

1 hour ago, Stu said:

Was your sketch the whole fov or just the positions around Neptune,

It was full fov- should have drawn a circle too. I think it was my 32mm plossl so about 50x but it might have been 24mm. Looking at a star chart the is a triangle of stars near Phi Aquarii and they’re visible in Knighty2112’s ep view image 4th post and if I’ve got confusing image flipping between newts and refractors they could be the ones?

2 hours ago, CraigT82 said:

Again I think this setup shows some good potential for when the better conditions return.

Looks like it- that’s a great image Craig. What does it look like through an ep? I know image stacking does amazing things  but the increase in resolution to what I’m seeing with v similar scope from my admittedly poor seeing location is really astonishing!

1 hour ago, Robert72 said:

Hope you are enjoying the posts.

I am Rob thank you- it’s incredible work and really inspiring. Not sure I’d call it beginners level though 😳😉

11 minutes ago, Stu said:

I'm really not sure Mark.

Thanks Stu- if it wasn’t then it did a very good impersonation 😂 The main star was very orangey and the pale bluish “Neptune” seemed to have disk-like width at higher mag without the flaring of a bright star. The Sky was quite clear for once and it seemed in right area. I did scan around and couldn’t find anything else that fitted the bill but it’s very possible, even likely, that I was looking at the wrong Neptune 🤦‍♂️

I “think” I found it but I’m a bit confused as there’s an equilateral triangle of dimmer stars nearby that aren’t showing in sky safari. But it does look a bit like a dimmer Albireo- am I seeing Neptune here? I tried to sketch what I’m seeing

Hi Gerry, I've heard you use that term before but what do you mean when you say "deepest eyepiece"? Do you mean that it sees deeper and is that a contrast thing? Mark

😞failed to identify them before the clouds rolled in- will have another go tomorrow should the sky allow

New secondary 😃

Can’t you tell inventor what materials each part is and specify density for cog calculation? I know you can in solidworks but no idea how accurate it is- should be accurate though

That’s quite the strangest image I think I’ve ever seen- it looks like a big red hand (or foot) holding out a star man - incredible

1 hour ago, jetstream said:

There seems to be a culture of "not cleaning" optics on SGL.

The worst I read was on a blog- can’t remember whose but they said words to the effect of you should never clean your eyepieces and if you do you may as well chuck them in the bin and buy new ones as they’ll never be the same again. Little bit extreme 😂

9 minutes ago, Ruud said:

Did you use light from below or above? I originally assumed you'd used a macro lens and light from above.

Hi Ruud, light from above, adjusting angle to get contrast. First post pic was just a 10x loupe held to back of phone.

PS the coatings on the Nikon scope eps are completely knackered- but it’s still a very useful tool 😉😂

Yes that’s a good point- maybe if I’d cleaned it sooner, whatever it was that caused this wouldn’t have had time to cause it!

Thanks Ruud, I tried the lens cleaner (isopropanol), breath , acetone and it’s not going anywhere so I do think it’s damage to the coating- like it just lifted off the glass. It’s very difficult to photograph but that’s what it looks like through a loupe and here I tried to capture it through a 40x inspection microscope but again difficult with phone. It’s not impact damage- the ep has been I thought well cared for and the lens is well recessed. I always keep them capped and in the carry case I made for them and I always leave the caps lifted off and the case lid open a crack overnight after dewy evenings use so they can air. Whatever it was that caused it it only affected this ep. Maybe it was some strange lifeform that took up residence in that cavernous eye socket and feasted on the coating but why only that one? I was using it at the lunar eclipse at a public event and quite a few people looked through it- maybe one of them had something on their lashes that did it 🤔 🤷‍♂️

I’m a bit gutted today after what happened to my Pentax XF12mm yesterday- my first foray into (to me) expensive eyepieces and not very old at all- bought brand new when I still only had my Tal-1 about six months ago.

I went through my eyepieces to give them a clean knowing some would have accidental light finger prints from rummaging around in the dark. Tbh I wasn’t expecting to have to clean the Pentax as the top lens is quite recessed and I don’t use it as often as others. But when I examined it it had collected a fair bit of detritus including what looked like a little bit of sleep dust so I went at it first with canned air then a Nikon wet wipe glasses cleaning cloth (fresh from foil pouch). No pressure was applied other than the springiness of the cloth.

This happened 😳 The little bit of sleep dust had adhered to the lens and when it came away it took a patch if the coating with it!!

Its only small and will likely not affect viewing but I’m a bit depressed about it now- my ocd is kicking in 😞

Apart from my BCO 10mm it’s the newest ep I have and all the others are probably decades old and without this kind of issue. One of the perils of purchasing new things I guess- they can only ever get damaged.

Anyway a cautionary tale of woe and just wondering if Pentax coatings have a reputation for being weak?

What’s that saying- keep your glass clean so you don’t have to clean it!

15 minutes ago, vlaiv said:

For this not to happen, you need most precise encoders that you can have - and those would be full resolution encoders (either incremental or absolute) on Alt and Az axis of the scope.

Yes- I was just questioning the need for absolute encoders - nice if the scope never gets moved but not really a necessity. Also resolution doesn't equal accuracy and like Horwig mentioned mounting accuracy can throw everything. Heidenhain (and others I'm sure) make some huge encoders for CNC machines etc which benefit from their diameter and very thick accurate glass grating  

I'm not getting the necessity of abs encoders on the alt az mount unless you mean you only need to calibrate once if you don't move the scope? They'd still need calibrating though. A multi star calibration with any type of encoder would sort out the geometry of the mount relative to sky wouldn't it? Of course you'd need encoders on the output to compensate slippage of the friction drive

It was very frustrating indeed but it’s true what they say- once you find these things the first time it gets much easier. I guess it’s knowing what to look for and remembering roughly where but I’ve had no issues finding it very quickly every night since. Also found Dumbell but it’s just an ill defined quite large grey blur. I think I definitely need an oiii filter and darker skies as I can’t see a trace of the Veil or North America...

Hi Rob, are you doing all this amazing work just to get a nice finish on the outside of the tube you’re making or will you be doing a production run and selling them?

On 11/07/2019 at 10:49, CraigT82 said:

That 8" F8 will blow your socks of on most targets to be honest!  

You may benefit from the cheap SW motor focuser.  With my 8.75" F7.5 the long tube makes tube vibrations pretty bad when focusing and the cheap motor makes things much easier and is easily adapted to most tubes/focusers.

Been considering adding a motor focuser to mine as indeed it’s very sensitive to focusing induced vibration though  I’m not sure I want the complication 🤔

Some brass for my new secondary holder 😃

10 minutes ago, CraigT82 said:

Ye old fullerscope is much steadier on this compared to it's old mk3 mounting..

What size is that fullerscope Craig? And what are those mods you’ve done to it? 

Clever- sounds like they made the scope too light 😉😂 Do those thin struts keep the uta rigid enough? Guess they must- interesting design!

What’s the spring for? Just to increase friction?

Thanks mr Niall- will give them a go next 👍