Modified cheap telescope. image quality? edges less blurry

[Sky Tinker]

Yes I have them correctly oriented.
The slightly more convex side of the crown goes into the concave side of the flint. and the less convex side of the crown faces the stars away from the observer.

thats how it came from factory at least.

I dont think I could flip any of the elements a different way and have a better image. the image quality seems fine visually. only a bit of CA on very bright light sources and stuff is a little bent/warped near the edges but i think thats just normal.

I could get a better diagonal (seems to be the cause of the blackout im having with my larger eyepieces) and improved or eliminated baffling and potentially also adding that flocking stuff throughout the whole thing. focuser. telescope tube. diagonal. everywhere I could use the stuff.
but I havent been able to find any available to buy from amazon. im only able to buy the stuff from there

I could instead buy some black 3.0 paint (super black matt paint) and just paint the whole thing up if that would work good enough. which seems to be a little cheaper and potentially easier to apply

That's correct, the slightly more convex goes down onto the concave of the flint. However, at the longer focal-lengths, the convex surfaces are not so easy to differentiate. Both curves are very shallow. With an f/15, it's nigh impossible, in which case one would need to flip the crown.

Yes, the black 3.0 might be the next best thing.

This is the closest I could find to flocking on Amazon. One reviewer, within another listing of the same material, stated that they used it for some older telescopes, and that it was better than paint...



If you choose that, cut into narrow strips before applying. I generally cut mine into 1.5" to 2" wide strips.

I'm thinking about getting this star-mirror for my 70mm f/4.3...

https://www.ebay.com/itm/GSO-1-25-90-de ... SwKgZdS6gj

That eBay seller, Agena Astro, has their own site...

https://agenaastro.com/gso-1-25-90-refr ... gonal.html

Amazon doesn't carry it.

[realflow100]

My telescope is F5.1 roughly
and I think i will just save up and get a 102mm refractor telescope. I found a good deal on one that seems to already have all of the things I would want in a GOOD telescope

wide focus tube to not have vignetting. and reasonable focal length. a much sturdier mount with fine tuning adjustments and a big 102mm aperture!

[Sky Tinker]

My telescope is F5.1 roughly
and I think i will just save up and get a 102mm refractor telescope. I found a good deal on one that seems to already have all of the things I would want in a GOOD telescope

wide focus tube to not have vignetting. and reasonable focal length. a much sturdier mount with fine tuning adjustments and a big 102mm aperture!

Tell us more about it.

[realflow100]

not much to say. its an F5.9 102mm refractor telescope with a huge focuser tube and looks nice too. and the specs are pretty good. even comes with a good variety of eyepiece sizes.

[Sky Tinker]

not much to say. its an F5.9 102mm refractor telescope with a huge focuser tube and looks nice too. and the specs are pretty good. even comes with a good variety of eyepiece sizes.

I'd say that that sounds like a Meade "Infinity" 102mm f/5.9 achromat.

[realflow100]

Is that one alright or better than what i have so far? it looks alright from what I can tell

[realflow100]

my only option to improve my telescope any further is to get a 2" focuser. and a 2" diagonal (I have a 1.25 to 2" adapter already that ive somehow obtained)
and somehow adapt the 2" focuser and diagonal to my telescope. then I could get a super bright field of view with NO vignetting/blackout or kidney beaning

OR to save up and get that 102mm telescope. which has a humongous wide focuser tube and could possibly adapt to a 2" diagonal to it to eliminate any possible vignetting

the diagonal included with my 70mm telescope causes some vignetting by itself even with a simple 20mm eyepiece and the focuser tube is really undersized. causing a lot of vignetting on the edges if i hold my eye too close. limiting the field of view and brightness a lot. uncomfortable too.

[Sky Tinker]

Is that one alright or better than what i have so far? it looks alright from what I can tell

The Meade "Infinity" refractor itself is okay, but the mount is an AZ-3 which has always been a bit problematic, especially nowadays in its cloned form. It's an old design, and needs to vanish from the marketplace.

Meade also makes the "StarPro" 102mm, at f/6.5 compared to the f/6 of the "Infinity" 102mm...

https://www.bhphotovideo.com/c/product/ ... 4gQAvD_BwE

The "StarPro" line appears to be superceding that of the "Infinity", perhaps. It's too early to tell for certain.

The eyepieces and barlow that come with both kits, I have the same set too, are nothing to write home about, but they will serve in the beginning. You would need to get a star-diagonal for the refractor, and for use at night.

[realflow100]

I dont have much problem with mounts I have a few available if i want to swap it to a different one to use with

Im not really a fan of higher magnification since its harder to find a target. so maybe would want the F6 one for its slightly wider view
I have 32mm eyepiece and a few other decent quality eyepieces which can give me a decent clear view if the included eyepieces aren't that great.

[Sky Tinker]

I found out the telescope focuser itself even though its shortened to half still causes some serious vignetting with larger eyepieces
and even the diagonal causes some vignetting too
Im at a loss as to how to fix that besides getting a better focuser assembly and better diagonal

Did you remove the baffles, within the OTA and the drawtube?

[Sky Tinker]

I dont have much problem with mounts I have a few available if i want to swap it to a different one to use with

Im not really a fan of higher magnification since its harder to find a target. so maybe would want the F6 one for its slightly wider view
I have 32mm eyepiece and a few other decent quality eyepieces which can give me a decent clear view if the included eyepieces aren't that great.

It is at the higher powers where "Wow!" and "Look at that!" exist; enough said.

[realflow100]

Yeah but higher powers the only thing visible here is stars and planets. No galaxies or nebula visible at higher magnifications at all
bortle 7 naked eye. and not much better with a telescope
can barely see the big dipper clearly only just make it out

No whirlpool galaxy visible either. trust me i tried. theres just nothing there at low power or high power with any of my combinations

Andromeda is a very faint fuzz with my 100mm orion skyscanner F4 telescope even at the lowest power 32mm eyepiece. Cant see it with naked eye even with averted vision.
even orion nebula is very faint you can barely make out the main dust pillar in it at 40x magnification and the "wings" shape just barely visible with averted vision!
Pleiades cluster looks great a low powers lots of stars visible to me. but no nebula at all.

And yes I took out all baffling of the telescope but the diagonal is causing serious vignetting issues from its limited clear aperture and the focuser tube is small too. barely bigger by a few millimeters than the tube on the end of the eyepieces that slot into the focuser.
if I take the eyepiece by itself without a diagonal or focuser tube at the focus distance from the telescopes objective where its in focus the "exit pupil" becomes almost twice as large and just about reaches the edge of the maximum field of view at 32mm

the whole sky looks like a glowy dull blue color from all the light pollution. even on a clear moonless night.
I'm also limited by other issues of glare from bright local streetlights within 100 feet in any direction for like a mile radius. and I cant travel anywhere either.
Im in orangeburg south carolina near gardens apartments. theres a field nearby but its really scary to go out at night there. too much crime in my area. and theres still streetlights visible all around shining brightly and glaring.
Cant even see the orion nebula naked eye with averted vision here. it just appears as 3 faint pairs of stars near orions belt to me.

[Sky Tinker]

Galaxies other than that of Andromeda, and nebulae, require much larger apertures to even begin to see them. What you need is a 10" Newtonian-Dobson, and the pricey eyepieces to tame its parabola. My largest operational telescope is a 6" f/5 Newtonian. It's only a little bit picky as to the eyepieces introduced to it.

I've not seen the Whirlpool myself. I've made a few attempts, but I simply don't have the "horsepower". I have seen the galaxy in Andromeda, as it swings towards the west. Even then it's quite dim, yet gratifying nonetheless.

Higher powers are required for the Trapezium and its environs within Orion's nebula, and preferably with a longer-focus telescope; at least 650mm, and with 900mm as an ideal.

In so far as your 70mm, with the draw-tube racked inward all the way, without a diagonal or eyepiece in place, you hold the telescope up to a bright screen or wall, and place your eye right up to the visual-back's opening and see if you can view the entire diameter of the 70mm doublet, all round. If you can, then all you'll need is a star-mirror diagonal. If you can't, then you'll need to open it up some more. If the telescope has a 1.25" draw-tube and visual-back, then yours will be easier to open up than mine was.

Yes, Orangeburg is well lit...



My area is not ideal. I could benefit from a trip myself...



But then, I used to live within that lit-up wasteland to the north, about 25 years ago. Back then, I had an 80mm f/11 achromat, therefore I know what you're up against, all too well; been there, done that. Still, I was able to see the "pockmarks" left behind on Jupiter's surface, with that telescope underneath that illuminated dome; the remains of comet Levy-Shoemaker.

[realflow100]

I can see the edges of the lens if i look in the empty focuser tube at an angle and not straight on. but straight on the edges look a bit cropped off. especially if im a few inches away from the focuser tube (where an eyepiece would be located) I have to look at even further angles to see the edges of the lens
like i have to move to the left to see the edge on the right

its a 1.25" focuser but the focuser tube itself is only a few millimeters bigger than 1.25" in diameter just big enough for an eyepiece to slot into it!
and its shortened a lot
When I look through my 32mm eyepiece just by itself at a plain wall. I see no vignetting.

if I take the focuser out of the telescope. and put an eyepiece in it with no diagonal. i see some vignetting with a 32mm eyepiece around the edges. and its harder to stay centered and keep it from vignetting across the whole view
and with the diagonal it vignettes to a small hole like 1/4th the size of the eyepiece if im too close to the eyepiece i need to have my eye away from the eyepiece by almost an inch to not have that vignetting

if I take an eyepiece and have the entire telescope focuser tube assembly removed so the back of the telescope is just open
and look through the eyepiece lined up to the telescope and at the right distance so its in focus i can see clearly and no vignetting at all with the eyepiece rubber cup right up to my eye. and i dont have to hold my eye at the perfect distance from the eyepiece anymore either.
but obviously i cant use the telescope that way,

With my 100mm orion skyscanner the focuser tube has a small collar thing that holds the eyepiece in the focuser tube. but the focuser tube itself is quite a bit wider and fairly short. so I dont get any noticable vignetting with that telescope and theres also no diagonal either. so even better.

[Sky Tinker]

I can see the edges of the lens if i look in the empty focuser tube at an angle and not straight on. but straight on the edges look a bit cropped off...

In that event, you do not have the full 70mm at your disposal. The openness is determined at the visual-back with the eye, only. The diagonal and eyepieces farther back will receive the full aperture, but only if you can see that full aperture as I had described and illustrated.

The baffle within the draw-tube of my 70mm f/4.3 achromat was molded as one with the tube. I had to cut the baffle out, and grind its remains down, including its molded sleeve. I couldn't believe that it had a sleeve in addition...

The draw-tube's run within the focusser had an extension facing the doublet. I cut that back as well.

Incidentally, I'm a bit confused as to which telescope you have in fact. My 70mm has a 300mm focal-length, and at f/4.3. The next size up is a 70mm with a 400mm focal-length, and at f/5.7. I'm thinking that that's the one you have, with the 400mm focal-length. Is there a branding on the OTA of your 70mm, like Gskyer, Aomekie, Toya, etc?

[realflow100]

Nope Mine is 70mm 360mm focal length. comes with the most flimsy shakey mount imaginable though. so i used my own mount
Emarth brand aimed for kids basically.

And mine had an internal baffle thing but its just a friction fit metal ring that just slips right out practically. i got rid of it too. unneccessary.

And there is significant vignetting with the draw tube and diagonal in use if I use eyepiece like 20mm or bigger unless i hold my eye at the perfect height hovering above the eyepiece about a half an inch away from it not even touching the eye cup

if i hold the eyepiece up to my eye directly. and have no focuser or diagonal. just putting the eyepiece hovering over the opening of the empty telescope tube i dont get any vignetting and i can have my eye right up to the eyepiece and see the full field of view. I can even add a 0.5x reducer and get such a wide field of view that the exit pupil almost fills the whole eyepiece when its in focus! absolutely crazy field of view. but thats only possible without a focuser tube or diagonal. and holding the eyepiece up to my eye floating it at the end of the telescope tube.

[Sky Tinker]

Ah, this one...



What made you choose it over the others, like the Celestron 70mm "Travel Scope", or the Barska 70/400; not that you made a bad choice, not at all. Regardless of branding, they're all made in same factories in China.

Yes, I got one of those flimsy mounts, too, with my Barska 70mm f/4.3. However, the mount can be used for something or other; perhaps a small pair of binoculars, or a small camera. I suspect that the head would need to be altered to accept one however.

I had removed the baffle from the OTA as well...

Did your draw-tube, of the focusser, have a baffle within it?

[Sky Tinker]

Here's the extension of the draw-tube's run I was describing earlier...

Before and after...

Click on the image to enlarge it. That opens the aperture up a bit as well.

You still have enough length to support the draw-tube when racking it in and out.

[realflow100]

oh nope thats not the problem at all. that part is fine. no baffle in the draw tube thing

there was one inside the focuser tube though i removed it with a screwdriver.

I went out tonight a bit and saw too many stars to count. there very faint but theres lots of them. plenty of stars visible anywhere i point the telescope pretty much

I tried bodes galaxy/cigar galaxy but was looking in the wrong spot this whole time and didnt bring stellarium with me on a phone. derp fail me lol

looking around the tip of the big dipper by the "cup" part of it. underneath it.

I didnt really choose that telescope for any specific reason just thought it was small and easy to carry around and stuff and it was the focal length i wanted.

[realflow100]

if I was able to fit a 2 inch or even 2.5 inch focuser assembly in my telescope with an eyepiece adapter I could get bananas wide field of view for easily finding things in the night sky

I actually did something kind of hilarious. I took two telescopes. point their front toward each other and put an eyepiece in both (20mm and 32mm) and looked through them and was shocked by the crazy wide field of view that it gave. but it was really hard to keep them aligned because one was on a tripod and the other i was just holding onto it in my hands