Buqibu

I tried to sketch Jupiter, The Double Cluster, The Owl Cluster and The Andromeda Galaxy, I know it isn't anything impressive but it was a very relaxing process and I really liked it. Hope to do more in the future

1 minute ago, Alan64 said:

It's this one, and that I had purchased in 2016...

https://www.celestron.com/products/astromaster-70eq-telescope

It has a very good doublet-lens, which is why I'm wanting to get a better focusser for it.  With that one, there is very little if any false-colour to be seen when viewing brighter objects.  I prefer long-focus refractors, and for that reason.  Also, the long focal-length plays well with my eyepieces.

Meade is, or rather was, Celestron's competitor, and just after Orion bought the company and its assets last June, I was able to get another 70mm f/12.9, a Meade, just the OTA, and to replace the Celestron if I can't get another focusser for it.  This Meade's focusser is standard, traditional...

Very nice! Yeah, even my short f6.5 refractor doesn't have too much false colour to speak of. I see you've also upgraded the mount, thats probably a very good idea considering the mount if the weakest part of these scopes. 

3 minutes ago, Alan64 said:

My bad, and my apologies, as I think that the draw-tube of yours is of metal, aluminum perhaps, silvery and sort of a frosted finish.

Maybe! May I ask what astromaster version you have?

3 minutes ago, Alan64 said:

No, it won't affect the views, I hope.  The reason I say that is because I don't like my own...

It looks like a sports car, no? <vroom vroom>

It has tongues...

Say ahhhhhhh...

It's an odd, proprietary design, and I can't render the draw-tube straight and true, and with no slop.  As a result, it's not lined up, collimated, with the doublet-lens at the front of the optical-tube.  I've been meaning to contact Celestron, and to ask for a normal, standard, traditional focusser from their "PowerSeeker" refractor line.  I can improve those, but not those of the "AstroMaster" refractors.

I would be smoking-hot over that denuded draw-tube, but as long as you're happy with it.

Yeah, Celestron cut a lot of corners with these entry level refractors. Not worth the headache, it does the job fine. Plus I checked Celestron's website, this particular 102az model does not have a chrome draw tube, so its not like I got cheated or anything.

3 minutes ago, Alan64 said:

This is the chrome-plated plastic draw-tube of my "AstroMaster" focusser...

What happened to your own?  Did the focusser's housing scrape it all off?  Did you receive it that way?  Did you purchase it new, or used?  If used, then I could understand it better, but not fully.  Like, I would wonder as to what the previous owner(s) did to it.

That's pretty far out, like beyond the galaxy in Andromeda.

No, bought it new, thats how it was from day one. Why, does it affect views or something?

53 minutes ago, Alan64 said:

With your permission...

It appears as this plastic draw-tube of my own, and where I had removed the chrome plating...

...same color.  Although, I see that the surrounding walls within your image are about the same colour, but it's still puzzling.

Ah, yeah thats how it looks. Its not chrome

32 minutes ago, saac said:

It's all in the marketing campaign , and wait until you see it painted in red . I'm putting my money down now  

Jim 

How else am I going to sell them🤣🤣

27 minutes ago, Alan64 said:

Why is the draw-tube of your focusser missing its chrome plating. 🧐

What do you mean?

4 hours ago, Stuart1971 said:

Hmmm, how is that dual speed, it’s just a bigger knob on the single speed….. 🤔🤔

Grab the original focuser - one speed

Grab the cardboard - 2 speed.

Obviously its not a true two speed gear focuser, just didnt have a more appropriate name for it😁

44 minutes ago, Alan64 said:

That's okay.  I'm glad you asked...

The way you do that is to deaden the entire inside of the telescope, from front to back, and to all sources of stray-light, whether natural(Moon), or artificial(porch, street and passing-automobile lights).  This is done with deep- and deepest-black, matte paint(spray-can or just a can), and flocking.  It's merely arts & crafts type work; for examples...

You can stick with just spray-cans, and spray from the can(where applicable), or spray paint into a plastic or metal container; a plastic lid from a jar, or a plastic container from a fruit or pudding cup.  They must be washed, of course, beforehand.  I lay a plastic sandwich-bag over the container, then a metal jar lid over that, and to keep the paint moist.  I do this between each short session of painting.  To thin the paint, if necessary, do not use paint-thinner, but better quality mineral-spirits.  Just a few drops into the container will re-moisten the paint.  As you can see in the image above, I use different sizes of artist-type brushes to apply the paint, and by hand.  I get those brushes cheap from my local super-department store.

Here, I've painted the edge of this doublet-lens all round...

Note the before-image, bottom-left.

The goal there is to make the lens(es) as invisible as possible, to prevent stray light from being reflected.  Ideally, we would not have anything between our eyes and the objects we're observing, but, unfortunately, our eyes, our pupils specifically, are very weak and make for poor telescopes, by themselves.  They can't even magnify; 1x is it.  That's why we all love telescopes.

Now, when painting the edges of lenses, invariably, unavoidably, some paint is going to get on the actual surface of the lens, there at the edge, all round, top and bottom.  You then take cotton-swabs, lightly dampened with 91% isopropyl-alcohol, then wipe the excess off away from the lens, but only one wipe per tip.  You can rotate the tip halfway round for a second wipe, but only if you get good at it.  You have to take care, however, not to remove any paint from the frosted, vertical edge all round.  It may sound difficult, but it isn't really.  You can source a scrap lens, just one, for practicing beforehand.  

I also paint the insides of the telescope tubes.  Before and after...

The telescopes that come from overseas, including yours, and practically all of my own, are painted on the inside, but the paint is lighter, tending towards grey, rather than a deep-black.  I call it "Synta grey".  Synta made your telescope, and several of my own as well.  Look at this before-image of my 6"/150mm f/5 Newtonian, without and with flash...

..."Synta grey".  It's such a lovely shade of grey, yet far removed from a deep-black.  There's some orange in that as well; rust, gads.

I also paint the screw-tips on the inside; everything that's glossy or shiny, and that could reflect stray-light.  This includes inside the draw-tubes of the focussers...

Also, in the case of refractors, the inside of the focusser housing...

Then, there is flocking.  Flocking is like very low pile carpeting, but for telescopes, and some accessories as well.  This is flocking...

Note how deep the black is; deeper than vast majority of black paints.  It is sold in rolls, usually, and it's self-adhesive.  You must wash the inside of a telescope tube first, dry it thoroughly, then gloss it throughout with a clear-gloss enamel...

The stuff I use smells to the high heavens above.  It's best to spray it outdoors, of course.  After the enamel cures and hardens, you cut the flocking into strips, and apply...

Within that Newtonian, there are only two things that reflect light: the primary-mirror, and the secondary mirror.  

This is the one and only instance where I flocked a focusser's draw-tube...

Here's an instance where I made a special flocked shield for a focusser's housing...

There was no need to paint the inside of the housing, behind that shield, in that instance.

In the end, you want the interior of your telescope...

...dead, and like the inside of Dracula's casket when it's closed, tight.

Wow, thanks for the long and detailed response. I should try this in the future, looks great for improving contrast. Cheers!

20 hours ago, Alan64 said:

What, no question as to how?

You should have a look through my achromats.

Sorry! Haven't had time to check back on the forum, indeed how would an achromat deliver views like an apo?

Absolutely, getting obsessed over details and optics only achieves frustration, I almost forgot why I even got into astro in the first place, to learn and relax in the beauty of the night sky, not to do optical figure estemations🤣🤣. Thanks for all the help 

1 hour ago, Alan64 said:

Well, you can use an Amici-diagonal at night, there's no law against it, but there's one thing about said diagonal that you might find very interesting.  There is such a thing called the "Amici line"...

Have you seen an illuminated line going through Jupiter like that?  Venus will exhibit that, too.  Saturn and Mars might, if at opposition, but then may not.  It's the brightness of the object that brings out that line.

I can't say I've seen that line, but I have noticed then when out of focus there is this line that divides the circle in two. This makes it so I can never achieve perfect focus in point objects like stars, for planets its not a big deal.

2 hours ago, Alan64 said:

A diagonal will never improve an image.  It can only degrade an image, if poorly-designed and manufactured.  The ideal is not to have a diagonal affecting an image at all, as though it hasn't even been placed into the telescope; invisible.  

Are you still using the diagonal that came with the telescope?  This is the one I'm talking about.  I have one too, and that came with my Celestron "AstroMaster" refractor...

If so, that is an Amici, erect-image diagonal.  It is primarily for use during the day, for land-based objects; birds in trees, ships at sea, that sort of thing.  For use at night, however, a star diagonal is preferred.  The word "star" says it all.  This is the same Amici, and compared to my Star...

Note the larger aperture of the Star, and for an object's light to pass through.  That is especially beneficial when using a low-power eyepiece, like a 32mm Plossl.  If you don't have one of those, such will provide the lowest power and widest view of the night sky.

There are two types of star-diagonals in the marketplace for your refractor.  One uses a glass-prism, like the Amici, but a star-type prism instead.  The other uses a mirror.  Your telescope is at f/6.5.  You can make use of either, a prism or a mirror.  A mirror will not introduce additional false-colour, but it is not as durable, and over the years.  

If you're located in the UK...

Prism... https://www.rothervalleyoptics.co.uk/celestron-90-degree-star-diagonal-125.html

Mirror... https://www.rothervalleyoptics.co.uk/antares-90-star-diagonal-125.html

If elsewhere, you should have enough information here to find one there.  In my opinion, this is the best 1.25" star-mirror diagonal on the planet...

https://www.firstlightoptics.com/diagonals/tele-vue-enhanced-aluminium-90-diagonals.html

This is an example of a better star-prism... https://www.firstlightoptics.com/diagonals/baader-t-2-prism-star-diagonal-32mm.html

Thank you! That's exactly the diagonal it has, I have an astromaster 102. Guess they have to make some compromises to make it suitable for terrestrial observing. Will check these out🙂

1 hour ago, John said:

If the diffraction rings only appear on one side of the star and / or do not appear concentric around the central airy disk then that suggests to me that there is some sort of collimation error in the optics. It could be the diagonal (if in use), the focuser or the objective lens tilt.

You should see something like these images inside the focus point, at focus and outside of the focus point:

 

 

Yeah, might be. Though because its a refractor I'd rather not tinker with it and risk messing it up. The views are otherwise quite sharp so its okay

A few days ago I made a post asking for advice because I could not see the airy discs in my 4 inch achro. Some people said it might be the seeing, others said maybe I wasn't magnifying enough. Well last night I was getting some unusally clear views of the planets, so I decided to try and see the airy discs again, maybe the seeing would permit. I tried and....nothing. The same smudgy shape I had  been describing. I decided as a last resort to remove my diagonal, maybe it was the cause. So I did. Put in the barlow plus Celestron Zoom, at 165x. After a few minutes adjusting my position (sore neck, sitting on the floor, you know the deal)...there they were. These 3 or 4 rings around Polaris. The star itself looked like a disc. I was very pleased, having solved this "issue" that had been bothering me for a while. Not that it matters that much, its a very simple thing, all telescopes do it, but maybe that was the thing that bothered me. Anyway, back on went the diagonal, the optical imperfections didnt outweigh its convinience😁. Thanks for the help! Just one question, the rings seemed to be only appearing in the lower part of the star, was this due to the seeing or maybe astigmatism or smth like that? Thanks

10 hours ago, orion25 said:

I see bands and moons! Good show!

Regards, Reggie 🚀

Thanks😀

6 minutes ago, paul mc c said:

Well done,couple of moons there too.

Thank you! 

Celestron AstroMaster 102AZ, using Celestron Zoom eyepiece plus barlow 2x, around 120 - 130x. Seeing was nice. Taken with handheld S10 Plus, pro mode, 1/50s exposure, ISO 400. Edited in Snapseed to enhance contrast and a few details.

Alright, thanks! I have been enlightened😀

If a reflector has a primary mirror diameter (aperture) of lets say 20 inches, and a secondary mirror obstruction of 30%, does that mean you effectively only have a usable aperture of 14 inches? (Because 70% of 20 is 14). Sorry if this is a very basic question, just wondering.

1 hour ago, F15Rules said:

Nice report 😊.

Yes, the GRS is easily visible in a decent 4" refractor under good conditions👍.

Don't be tempted to go to really high magnification on Jupiter..I find that 120-140x is often enough, and any extra can make the view more "mushy"..

Conversely, Saturn will often take more power..

Dave

Thank you! Cant wait to check it out😁

That sounds odd, maybe some planes doing manouvers? 🤷

Brought out my 4 inch achro, using the Celestron Zoom eyepiece, coupled with a barlow 2x. Seeing started out as ok but it kept getting better. For some reason Jupiter looked clearer to me than Saturn, even though it was lower in the sky. I was able to see all 4 galillean moons, Io and Europa were very close together, almost as if they were a double star. Callisto was standing at the far left of the fov, Ganymede to the far right. I was able to see 3 bands, the 2 main belts and the little thin one above the north belt. I also saw variation in colour, from the dark brown of the belts, to the white in between, to the cream colour of the overall sphere. One of the best views I've gotten in a long time. Most of the time i stuck to 6mm (110×), but I could push it to 4mm (165x), it was a bit dim though. Then The Moon came out and I also enjoyed looking at that. Very nice session overall. One of these days I hope to catch a glimpse of the Great Red Spot. Is it visible in a 4 inch?