Refractor for planets, mostly visual, 4" or 5"

[JeremyS]

37 minutes ago, andrew s said:

Sorry it was intended as humour, ligh relief. 

No offense was intended to anyone. The emoji was ment to signal humour. 

Regards Andrew 

I enjoyed it Andrew

Just don’t expect me to contribute to your crowd fund 🤣

Edited February 8, 2021 by JeremyS

[andrew s]

2 minutes ago, JeremyS said:

I enjoyed it Andrew

Just don’t expect me to contribute to your crowd fund 🤣

That's ok, just contribute your eyes for the trials. 😩😭

Regards Andrew 

[jetstream]

1 hour ago, JeremyS said:

Do you mean adaptive optics? Adaptive optics help respond to atmospheric distortion. Telescopes with such systems measure the atmospheric distortion and modify the optical train in real time, I.e they are not predictive. They operate at 100 to 1000 Hz.

Please tell me you don't have one of these too!!

I can't keep up!

[jetstream]

44 minutes ago, andrew s said:

That's ok, just contribute your eyes for the trials. 😩😭

Regards Andrew 

Did you find out how much?

[Deadlake]

49 minutes ago, JeremyS said:

I enjoyed it Andrew

Just don’t expect me to contribute to your crowd fund 🤣

I think I saw a quote of CN for $50000 to build an adaptive setup, a snip Jeremy and your from room will not look like a Tak showroom! 😄

[jetstream]

@Deadlake- what scopes do you have? just curious and sorry if you posted the answer already. I'm reorganizing the line up here.

[Deadlake]

16 minutes ago, jetstream said:

@Deadlake- what scopes do you have? just curious and sorry if you posted the answer already. I'm reorganizing the line up here.

I have a Vixen SD103S on a SXP2 mount and a ScopeTech zero.

I have a APM 130 mm/ F6 ( Phenolic tube and starlight focuser) on route. Looking forward to it as it has a Strehl > 0.98, which is high for an F6. 

The tube rings are stuck in transit at the border..... 
 

Edited February 8, 2021 by Deadlake

[jetstream]

1 minute ago, Deadlake said:

I have a Vixen SD103S on a SXP2 mount and a ScopeTech zero.

I have a APM 130 mm/ F6 ( Phenolic tube and starlight focusers) on route. Looking forward to it as it has a Strehl > 0.98, which is high for an F6. 

The tube rings are stuck in transit at the border..... 
 

Great choices!

I have found that (for me) every little bit from 90mm up to 120mm-130mm makes a very nice difference. From here I like to go to 200mm on up, with 250mm being a great all round aperture.

I looked at the APM LZOS but at the time it seemed as if availability was going to be an issue according to Marcus. I drool over those lenses. Then TEC didn't reply to enquiries on a 140mm and so Tak was chosen (once a supplier was found-that was the issue). Almost bought the TOA130 but very heavy and quite a bit more.

I found buying a good frac here to be challenging. Truly happy with the Tak I have.

Eagerly waiting reports with the APM!

[Deadlake]

5 minutes ago, jetstream said:

Great choices!

I have found that (for me) every little bit from 90mm up to 120mm-130mm makes a very nice difference. From here I like to go to 200mm on up, with 250mm being a great all round aperture.

I looked at the APM LZOS but at the time it seemed as if availability was going to be an issue according to Marcus. I drool over those lenses. Then TEC didn't reply to enquiries on a 140mm and so Tak was chosen (once a supplier was found-that was the issue). Almost bought the TOA130 but very heavy and quite a bit more.

I found buying a good frac here to be challenging. Truly happy with the Tak I have.

Eagerly waiting reports with the APM!

The availability is an issue, so I jumped on LZOS. For instance the six months from last November 2020, the dealer had only two 130mm F6 lens cells available and around four 152 mm tubes built but no lens to place in them. Everyone has gone premium APO crazy!! I looked at the 130 mm TOA, but in the end I needed a fast APO that would support NV and the TOA weight/cost was to high. Of course I blame @GavStarand @John for it... 

[jetstream]

2 minutes ago, Deadlake said:

fast APO that would support NV

Funny you mention NV- this might be part of the re org but where I live in Canada makes buying things challenging ie shipping costs, customs costs etc etc.

Way off topic and anyone feel free to boot me from the thread for it- I've wondered how an SCT with the f2 would work? too narrow fov? My 90mm Raptor f7 is on deck in the meantime.

[JeremyS]

9 minutes ago, jetstream said:

Funny you mention NV- this might be part of the re org but where I live in Canada makes buying things challenging ie shipping costs, customs costs etc etc.

Way off topic and anyone feel free to boot me from the thread for it- I've wondered how an SCT with the f2 would work? too narrow fov? My 90mm Raptor f7 is on deck in the meantime.

NV with SCT in f/2 (celestron Fastar) mode? Won’t your head get in the way? 😬 

[KP82]

20 minutes ago, Deadlake said:

The availability is an issue, so I jumped on LZOS. For instance the six months from last November 2020, the dealer had only two 130mm F6 lens cells available and around four 152 mm tubes built but no lens to place in them. Everyone has gone premium APO crazy!! I looked at the 130 mm TOA, but in the end I needed a fast APO that would support NV and the TOA weight/cost was to high. Of course I blame @GavStarand @John for it... 

Availability and now import tax after brexit are always issues when buying premium APOs in the UK. The only brand that can be reliably sourced within the country is Tak (not with the current pandemic I suppose). All the others will have to be purchased directly from the US (AP, TEC) or EU (LZOS, CFF).

Edited February 8, 2021 by KP82

[Deadlake]

23 minutes ago, jetstream said:

Funny you mention NV- this might be part of the re org but where I live in Canada makes buying things challenging ie shipping costs, customs costs etc etc.

Way off topic and anyone feel free to boot me from the thread for it- I've wondered how an SCT with the f2 would work? too narrow fov? My 90mm Raptor f7 is on deck in the meantime.

A little discussion here:
 

@GavStar has the C11 working with a reducer very well. I don't know anyone with the Fstar working at all, or how would you view. You could get a Boren-Simon PowerNewt astrograph reflector down to F2.8 ish. The APM will get down to F2.4 after the Televue compressor is used. This being a refractor thread, only do that if you don't like perfectly round stars.. 😃

Edited February 8, 2021 by Deadlake

[jetstream]

4 minutes ago, JeremyS said:

NV with SCT in f/2 (celestron Fastar) mode? Won’t your head get in the way? 😬 

Can you explain Jeremy?

[JeremyS]

2 minutes ago, jetstream said:

Can you explain Jeremy?

Well, if I tried to place my eye at the Fastar focus of my C9.25 (instead of a CCD camera), my head would obscure the view of the telescope unless I used the services of a headshrinker 🤣

[jetstream]

1 minute ago, JeremyS said:

Well, if I tried to place my eye at the Fastar focus of my C9.25 (instead of a CCD camera), my head would obscure the view of the telescope unless I used the services of a headshrinker 🤣

Ok I knew that 😄

Just makin sure you did

[JeremyS]

Just now, jetstream said:

Ok I knew that 😄

Just makin sure you did

I might get away with a C14, though. 
My hat size is 7 1/4.

But my lockdown hair is probably not going to help.

[jetstream]

32 minutes ago, Deadlake said:

t in the end I needed a fast APO that would support NV

Do you have a reducer?

Talking NV is like walking on thin ice

[Deadlake]

1 minute ago, JeremyS said:

I might get away with a C14, though. 
My hat size is 7 1/4.

But my lockdown hair is probably not going to help.

Didn't realise you had a Celestron show room in the house as well?

Edited February 8, 2021 by Deadlake

[jetstream]

1 minute ago, JeremyS said:

I might get away with a C14, though. 
My hat size is 7 1/4.

But my lockdown hair is probably not going to help.

I could use my (chrome) head as an artificial star to collimate then?!

[Deadlake]

3 minutes ago, jetstream said:

Do you have a reducer?

Talking NV is like walking on thin ice

No, I'm going to digest the APM first then get around to a NV device. I purchased the APO from Rupert@Astrograph, they sell OVNI NV so I know they work together. NV can be trial and error and a 3d printer... 😄

Edited February 8, 2021 by Deadlake

[jetstream]

7 minutes ago, Deadlake said:

No, I'm going to digest the APM first then get around to a NV device. I purchased the APO from Rupert@Astrograph, they sell OVNI NV so I know they work together. NV can be trial and error and a 3d printer... 😄

Yes too many things to try at once can make things interesting in the wrong direction.

Now I need a Petzval!

Btw in the linked thread  mirror reflectivity was discussed- Celestron is most likely telling the truth about the 85% IMHO. In talks with a top coater and optician it came to light that reflectivity specs are "nominal" and can vary across the surface a bit. The best coaters get 95%-96% and the best mass produced mirrors about 92%-93%, both subject to variation. The best ones have less variation.

Not a frac topic but interesting-and might apply to lens coatings. My 90 SV is extremely sharp and with lower transmission than the TSA120.

[Deadlake]

9 minutes ago, jetstream said:

Yes too many things to try at once can make things interesting in the wrong direction.

Now I need a Petzval!

Btw in the linked thread  mirror reflectivity was discussed- Celestron is most likely telling the truth about the 85% IMHO. In talks with a top coater and optician it came to light that reflectivity specs are "nominal" and can vary across the surface a bit. The best coaters get 95%-96% and the best mass produced mirrors about 92%-93%, both subject to variation. The best ones have less variation.

Not a frac topic but interesting-and might apply to lens coatings. My 90 SV is extremely sharp and with lower transmission than the TSA120.

To be honest your 24" dob would be you best bet (around F4??)  and then for a wider field the TSA120 would be quite good, maybe not worth get another scope for. Petzvals are not a silver bullet, building one that works in low temperatures where all the lens have to move together is a tough ask.

Another thread for NV telescopes its here:

https://www.cloudynights.com/topic/740879-130-mm-apo-for-nv/

However not sure if flat field scope for NV is a requirement or people just get lucky those scopes work well with the NV device.  

Edited February 8, 2021 by Deadlake

[jetstream]

3 minutes ago, Deadlake said:

To be honest your 24" dob would be you best bet (around F4??)  and then for a wider field the TSA120 would be quite good, maybe not worth get another scope for. Petzvals are not a silver bullet, building one that works in low temperatures where all the lens have to move together is a tough ask.

I thought about the f4.1 too...

but I'm becoming ceased up a bit here with OA and that monster is a challenge - not sure if the Doc is on board with it after the operation(s). Funny how fast things can change.

[Deadlake]

2 minutes ago, jetstream said:

I thought about the f4.1 too...

but I'm becoming ceased up a bit here with OA and that monster is a challenge - not sure if the Doc is on board with it after the operation(s). Funny how fast things can change.

Jeff Morgan on CN has a 130 mm F7 and he has published quite a few amazing photos taken using NV. He talks about building a huge DOB however given what he sees using NV not much motivation.

https://www.cloudynights.com/topic/686008-night-vision-image-gallery/page-3#entry10212746

You will loss visual scale with a smaller aperture, maybe a compact astrograph Newt + NV would help, less weight?