How do I make an astronomy refractor a bird watching one?

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How do I make an astronomy refractor a bird watching one?

Post by Montana »

Bit of a quick question, I don't have much time. I have only just realised that my Technosky 60mm isn't the right way up. It is so beautiful to look through compared to my very old birdwatching telescope.

So I read up that a star diagonal makes the image the right way up but mirrored (that's OK in an emergency). A prism diagonal makes it the right way up and the right way round.

So I thought, great, I have a star diagonal (Televue everbright) and tried it. It works great everything the right way up but mirrored. I can cope with that, however, I can only reach focus when the objects are near. The oak tree about 200-300 metres away I can't focus on. There doesn't seem to be enough in focus. That seems to make no sense to me, why would you have an astronomy telescope that can't reach focus more than 300m away? surely I wouldn't be able to focus on the moon or stars with this star diagonal in then? what am I missing? Do I need to buy something very quick instead as I can't cut the telescope up to get more inward focus. I just don't get it.
Any help would be great.

Alexandra
Equipment which doesn't work to focus:
Tecnosky 65Q f/6.5 Quadruplet APO - 2" Focuser Aperture: 65 mm Focal Length: 420 mm
Televue 2” Everbrite Mirror Diagonal
SMC Pentax XF zoom eyepiece 6.5-19.5mm
Canon EOS 700D camera


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Re: How do I make an astronomy refractor a bird watching one?

Post by Radon86 »

Hi Alexandra,

I was just checking my work schedule for next week, and I came across your post.
I think, a quick may of getting to focus would be to try a Barlow x2 lens. That would bring the focus further out I think.

I had problems focusing with the Quark and a focal reducer which took about 1 year to solve.
Hopefully this will help.

The other thing would be to try an extension tube. I have lots of these now, and they are not cheap !

Hope the barlow lens works. It should be a lot easier than solar imaging !

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

Thank Magnus, I've just tried that and it makes it infinitely worse, I can only focus on objects very near in my garden now with that. I need to be able to focus a long way away and I can't get enough focus inwards (not outwards). If it was outwards I have plenty of extension tubes. I don't understand why an astronomical scope with a star diagonal can't focus at greater than 200m? surely that is pointless and no good for birdwatching either. This has astounded me.

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by marktownley »

The 2" diagonal is eating the back focus on the scope, you need to use something 1.25" (mirror/prism etc - not sure what you would need).


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Re: How do I make an astronomy refractor a bird watching one?

Post by EGRAY_OBSERVATORY »

Hello Alexandra.

I know of the quickest and cheapest way of getting two telescopes (without requiring any add-on's at all).

You are already likely to own two suitable telescopes ??? Now she is wondering - what an Earth is Terry talking (or about to talk) about.

Well it's quite simple Alexandra - Have you not got a pair of Bino's ???

Remember also our previous discussion about the Image Stabilised Binoculars, which are primarily used/made for watching birds ???
(in my case the only birds I want to have a close-look at are :- (now don't jump the gun Alexandra) - are aeroplanes !!!

Your thoughts are welcome and even if you don't already posses two telescopes in one package, they are not expensive and you might even find the magnifying ones that can get you so close, that you fink you can actually touch the targets... !!!

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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

Thanks guys, I'm a bit last minute, I hoped to take these on holiday with me next week to look for porpoise and seabirds far out in the sea Loch. I bought a Canon to fit this scope for the 2017 eclipse and had the bright idea of taking it with me. It works great straight through but everything is upside down. I'm not sure I have the time to buy something.

Mark, I have just tried a cheapo 1.25" star diagonal which was free with the hubby's Celestron Omni and it works great! but it means I can't use the Canon :( oh well, it is much clearer and brighter than the old birdwatching telescope but about 3x the weight. I need to be more organised in future. I still don't get why the expensive Televue diagonal is so useless and the cheapo one works great?

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by Radon86 »

Montana wrote: Sun May 09, 2021 2:43 pm Bit of a quick question, I don't have much time. I have only just realised that my Technosky 60mm isn't the right way up. It is so beautiful to look through compared to my very old birdwatching telescope.

So I read up that a star diagonal makes the image the right way up but mirrored (that's OK in an emergency). A prism diagonal makes it the right way up and the right way round.

So I thought, great, I have a star diagonal (Televue everbright) and tried it. It works great everything the right way up but mirrored. I can cope with that, however, I can only reach focus when the objects are near. The oak tree about 200-300 metres away I can't focus on. There doesn't seem to be enough in focus. That seems to make no sense to me, why would you have an astronomy telescope that can't reach focus more than 300m away? surely I wouldn't be able to focus on the moon or stars with this star diagonal in then? what am I missing? Do I need to buy something very quick instead as I can't cut the telescope up to get more inward focus. I just don't get it.
Any help would be great.

Alexandra
Equipment which doesn't work to focus:
Tecnosky 65Q f/6.5 Quadruplet APO - 2" Focuser Aperture: 65 mm Focal Length: 420 mm
Televue 2” Everbrite Mirror Diagonal
SMC Pentax XF zoom eyepiece 6.5-19.5mm
Canon EOS 700D camera
Hi Alexandra,

I just realised that the situation depends on whether you are imaging with a Canon or just observing with an eyepiece.

1) With an eyepiece and diagonal, you should get focus within a few metres. In fact, my 70mm ED refractor focuses objects near the back garden easily.
2) If you are imaging with the Canon 700D, you will need to remove the diagonal. I assume you are connecting the Canon camera with the T-ring and a 2 inch camera adaptor to the back of the OTA; no diagonal is needed.

Hope this works better for you.

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

That's right Magnus, however all the birds will be upside down :( somehow I thought a star diagonal would allow you to see things the right way up and image with it. It seems not, the Televue can't achieve focus and is next to useless, the el cheapo diagonal works great but not with the Canon.

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

My little mind is completely baffled. I put the Canon on the telescope in a straight through position and everything is the right way up (from what I seem to remember at the eclipse). Took the Canon off and placed the eyepiece in and everything is upside down. So it is the Pentax Zoom which is upside down. Why is the eyepiece upside down?

So I am sorted now, the Canon straight through is the right way up, then if I use the el cheapo 1.25" star diagonal with the eyepiece I am right way up but back to front. I'm baffled why the eyepiece is upside down, I thought it was refractors which were upside down.

Anyway, problem solved. Thanks for the brain storming session.

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by Radon86 »

HI Alexandra,
Good to know its sorted.
I think you need a proper diagonal for daytime viewing. I bought one in the past, they are quite inexpensive.
The imaging with the Canon ? I also think it is the right way up with the straight through imaging setup, I did not double check that though.
Here is what I was going to post. Going from infinity to the back garden is about 7mm of in-wards focus.
IMG_6891-eyepiece.jpg
IMG_6891-eyepiece.jpg (623.09 KiB) Viewed 2144 times
IMG_6892-imaging.jpg
IMG_6892-imaging.jpg (629.17 KiB) Viewed 2144 times
Hope this helps.

Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
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Re: How do I make an astronomy refractor a bird watching one?

Post by DeepSolar64 »

My little Astro-Tech AT72EDII refractor makes an excellent bird-watching and terrestrial scope. It gives sharp false color free views and is capable of low power wide fields but is also capable of well over 100x with appropriate eyepieces. However in some cases a 45 degree diagonal may be more appropriate to a 90 degree one. A high quality zoom eyepiece would be useful too. An amici prism diagonal would be nice too. It's up-down and left-right image correct.


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Re: How do I make an astronomy refractor a bird watching one?

Post by GreatAttractor »

Montana wrote: Sun May 09, 2021 6:26 pm I put the Canon on the telescope in a straight through position and everything is the right way up (from what I seem to remember at the eclipse). Took the Canon off and placed the eyepiece in and everything is upside down. So it is the Pentax Zoom which is upside down. Why is the eyepiece upside down?
Note that a refractor without accessories is just like a photographic lens; it creates a reversed image (i.e., flipped up/down and left/right; or, equivalently, rotated by 180°), and DSLRs and our astrocams account for this when reading out the sensor (DSLR's optical viewfinder does too), so a photo will be in normal orientation. Visually in the eyepiece, though, you see the reversed image.


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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

Thanks Filip, that makes complete sense now, now I understand what on earth is going on :hamster:

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by nebulabru »

Hello ,
I now have a TS 60 ED that with an amici prism or erector prism I can focus at any distance, up to infinity, and with the image corrected perfectly, I had your problem a few years ago with the Takahashi FS60 refractor ... to this type of telescopes lack "intra-focus", that is, inward travel to be able to focus at any distance, in your case at 300 meters, I solve it with a low-profile eyepiece holder, one from Baader, so that my focusing tube gain those millimeters inward that I needed.
luck and greetings
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Re: How do I make an astronomy refractor a bird watching one?

Post by Montana »

Thanks nebula :) I have one of those and I did actually use it in the end, but don't you find it is still back to front? When I was using it I had to learn if the bird went right, move the scope left. By the end of the holiday my brain had just about learned it :)

Alexandra


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Re: How do I make an astronomy refractor a bird watching one?

Post by nebulabru »

Alexandra,
truly with the erector prism the image is presented as it really is. The refractor that I have now has a lot of intra and extra focus travel ... and I have no problem. With the previous one (Takahashi FS 60) it gave me many problems ... but I managed to solve it ... almost, because it did not work with all my eyepieces.
sincerely


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Re: How do I make an astronomy refractor a bird watching one?

Post by nebulabru »

Alexandra,
truly with the erector prism the image is presented as it really is. The refractor that I have now has a lot of intra and extra focus travel ... and I have no problem. With the previous one (Takahashi FS 60) it gave me many problems ... but I managed to solve it ... almost, because it did not work with all my eyepieces.
sincerely


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