Jump to content

290128050_ConstellationBanner.jpg.6eb5d1fe82e0853d4c3b80a745d12d74.jpg

Cheap achro refractors


Recommended Posts

7 hours ago, vlaiv said:

Have no idea, but I'll post my findings as soon as I get the chance to inspect them.

Given the holiday seasons, I expect them to arrive next year (at least 30 days shipping).

That will give me plenty of time to design and print focuser and order aluminum tubing locally (or maybe I should wait and measure lens themselves? Not sure, never designed a lens cell before).

Can't wait for your report, what about spacing between the two elements hows that calculated? I wish you well, might have ago once you have guinea pigged it.

Link to comment
Share on other sites

9 minutes ago, Coco said:

Can't wait for your report, what about spacing between the two elements hows that calculated? I wish you well, might have ago once you have guinea pigged it.

as far as I can tell - both lenses are marked for orientation and spacer is included.

If not, it will be a little trial and error with artificial star. I've seen few cases where lens was not optimized with spacing and changing it improved spherical aberration substantially, so it's worth checking out anyway.

 

  • Like 1
Link to comment
Share on other sites

7 minutes ago, vlaiv said:

as far as I can tell - both lenses are marked for orientation and spacer is included.

If not, it will be a little trial and error with artificial star. I've seen few cases where lens was not optimized with spacing and changing it improved spherical aberration substantially, so it's worth checking out anyway.

 

Ive had this in my cart for months, thought it would be worth a punt, at least it would be a good learning curve. 131mm f/7.6

https://www.aliexpress.com/item/1005003002741307.html?gatewayAdapt=4itemAdapt

 

Link to comment
Share on other sites

1 minute ago, Coco said:

Ive had this in my cart for months, thought it would be worth a punt, at least it would be a good learning curve. 131mm f/7.6

https://www.aliexpress.com/item/1005003002741307.html?gatewayAdapt=4itemAdapt

 

That is much more serious than I was prepared to start with :D

At first, I was thinking I should go with 60 or 70mm, but then I decided to "go all in" and went for 80mm one :D

 

  • Haha 1
Link to comment
Share on other sites

Lens element spacings on budget items are usually calculated to provide the best compromise between spherical aberration and chromatic aberration.  You can alter the spacing to improve one at the expense of the other, no free lunch!.  Bear in mind, little or no special figuring will be applied although with mass production you may strike lucky.      🙂

  • Like 3
Link to comment
Share on other sites

I think these little scopes can be awesome. Here's my 60mm F11.6 Carton Comet Seeker. I know, it doesn't sound like much of a comet seeker at F11.6 let alone with a 60mm objective, but for its time it was quite short yet still is pretty much free of any visible CA. The Carton also boasts a 1.25" stock focuser which again is unusual for a 60mm of its time. This of course means I can use some high quality eyepieces to get the best out of this beautiful little objective. The scope is also capable of using a binoviewer which really gives it a punch above its aperture class.

Below are some pic's and a sketch of mars from this evening (07/12/22).  

 

2022-04-08 15.28.22.jpg

 

IMG_20220408_091310.jpg

1672608345356_2023-01-01 20.10.53.jpg

Edited by mikeDnight
  • Like 2
Link to comment
Share on other sites

I think these little scopes can be awesome. Here's my 60mm F11.6 Carton Comet Seeker. I know, it doesn't sound like much of a comet seeker at F11.6 let alone with a 60mm objective, but for its time it was quite short yet still is pretty much free of any visible CA. The Carton also boasts a 1.25" stock focuser which again is unusual for a 60mm of its time. This of course means I can use some high quality eyepieces to get the best out of this beautiful little objective. The scope is also capable of using a binoviewer which really gives it a punch above its aperture class.

Below are some pic's and a sketch of mars from this evening (07/12/22).  

IMG_20221207_195401.thumb.jpg.32b8e6e0304cf249c89f40496b9ddf92.jpgIMG_20221207_195422.thumb.jpg.21ff35928f0a85ff6d32baa3c4f1d2cf.jpg

Link to comment
Share on other sites

I think these little scopes can be awesome. Here's my 60mm F11.6 Carton Comet Seeker. I know, it doesn't sound like much of a comet seeker at F11.6 let alone with a 60mm objective, but for its time it was quite short yet still is pretty much free of any visible CA. The Carton also boasts a 1.25" stock focuser which again is unusual for a 60mm of its time. This of course means I can use some high quality eyepieces to get the best out of this beautiful little objective. The scope is also capable of using a binoviewer which really gives it a punch above its aperture class.

Below are some pic's and a sketch of mars from this evening (07/12/22).  

IMG_20221207_195401.thumb.jpg.32b8e6e0304cf249c89f40496b9ddf92.jpgIMG_20221207_195422.thumb.jpg.21ff35928f0a85ff6d32baa3c4f1d2cf.jpg

Link to comment
Share on other sites

My Svbony 48P achro, f5.5 with a 2", 2 speed focuser, retractable dew shield, all for $340 C does not look or perform or feel like a cheap scope. Wih my Morpheus eyepieces or my several Svbony zooms the views on dsos are pinpoint right to the edge and the planets are as they should be. Some achros perform like apos, many times for a lot less $'s. Its an up and coming steal !

4E4BDF90-333C-49F3-81B0-E579BAFC7E81.thumb.jpeg.73ea2aef8542e44d66d39d89e8b308df.jpeg

C406A150-12C8-4457-AF4F-D708CFF1DD3F.thumb.jpeg.21fa4fa38dac6aba96eb38940745de8e.jpeg

  • Like 2
Link to comment
Share on other sites

18 minutes ago, mikeDnight said:

Sorry for the three posts. For some reason the site isn't registering the post has been sent.

I have had the same recently several times with posts seemingly not updating with a message that I need to wait 6 seconds..

Alan

  • Like 1
Link to comment
Share on other sites

I shouldn't show this one but I will, its my mid 1959 60mm Tasco Model 304, f15 a forrunner of all the 60's and newer models. I can use 1.25" eps as well.

DC1948C0-EBF9-4635-8D04-BA191D0D51AE.jpeg.0f44ad2bf156396833a958dbfd17bd75.jpeg5B04B621-F56A-4794-96CE-8CDCA678C8FB.jpeg.e96f255decc1f8087afc1c78549d54b6.jpeg5B04B621-F56A-4794-96CE-8CDCA678C8FB.jpeg.e96f255decc1f8087afc1c78549d54b6.jpeg

Edited by LDW1
  • Like 4
Link to comment
Share on other sites

4 minutes ago, Alien 13 said:

I have had the same recently several times with posts seemingly not updating with a message that I need to wait 6 seconds..

Alan

Thats what happened to my post above,I don't know how to delete the last pic.

Edited by LDW1
  • Like 1
Link to comment
Share on other sites

Hope this is ok for me to join in with?  My little Opticstar AR80s that I picked up fairly recently.  I've been able to use it yet as it is so small and light, I needed to source a 1kg weight for my mount to balance!  I'm a suckered for a short tube frac, been on my wish list for years but, the itch is not yet scratched...1305019879_image(4).jpeg.a6e683cf027186c956e54b1828acf8f4.jpeg180987199_image(3).jpeg.64df45ff78f620aebe255f4516018523.jpeg148956726_image(6).jpeg.d2ab7c38d5001b627b8f7fa7a0b845a0.jpeg

  • Like 1
Link to comment
Share on other sites

On 02/12/2022 at 22:14, Philip R said:

A few weeks, I got a ‘tip-off’ of a local house clearance as some of the content was astronomy related. 

Anyway... not sure if this is the right place, but to cut a long story short; it was an Aladdin’s cave of astro and photo-equipment. A few OTA’s caught my eye and one was a Meade 102mm/focal length about 900mm. My question is: how much is it worth? and should I get it?

I did not leave empty handed and I managed to find a cradle, albeit slightly oversize my ‘re-modded’ ETX105 for £5. The cradle is going to need some packing for a snug fit.

After giving it some thought over the past days, I decided to purchase it. It is the Meade DS-2102 [OTA and cradle only - no end caps]. I offered the seller £50... He said and I quote: "Don't be silly. Just give me £20😊

I will have to drill a couple of holes in the cradle to attach the dovetail bar... and place an order some pipe end caps for the e/p end and objective cell from the online warehouse in the far-east... 😉

Edited by Philip R
  • Like 1
  • Haha 1
Link to comment
Share on other sites

  • 3 weeks later...
On 15/10/2022 at 07:42, wookie1965 said:

I did smooth as silk now.

20180822_111008.jpg

20180822_112322.jpg

20180822_110905.jpg

Sadly Sold this now I just have the 4" Tal now which I would like to change the focuser on I have plans for that, A fellow SGLer has said he can 3d print an adapter just need a focuser now.

Link to comment
Share on other sites

On 07/12/2022 at 21:29, LDW1 said:

I shouldn't show this one but I will, its my mid 1959 60mm Tasco Model 304, f15 a forrunner of all the 60's and newer models. I can use 1.25" eps as well.

DC1948C0-EBF9-4635-8D04-BA191D0D51AE.jpeg.0f44ad2bf156396833a958dbfd17bd75.jpeg5B04B621-F56A-4794-96CE-8CDCA678C8FB.jpeg.e96f255decc1f8087afc1c78549d54b6.jpeg5B04B621-F56A-4794-96CE-8CDCA678C8FB.jpeg.e96f255decc1f8087afc1c78549d54b6.jpeg

in 1959 it wasn't cheap 😄  its a beauty!

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.