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Best beginner refractor for basic astrophotography

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#1 cuivienor

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Posted 24 April 2013 - 08:06 PM

Hi,

I am looking at getting into simple wider-field astrophotography using an iOptron smart eq pro mount, and a small refractor (plus Meade DSI Pro II mono and filter set). My experience up to now has been with my LT6 and LS8, which limited the exposures and had very concentrated field. My requirements are as below:

- It has to be small: length should be less than 40/45 centimeters, so that I can actually carry it to dark sites (I live in the middle of Tokyo). Also I can more easily hide it in my small apartment so it doesn't annoy my wife
- It has to be light, ideally less than 3-4 kg (see above)
- It has to be maximum around 700 dollars
- It has to be available in Japan (this immediately rules out Celestrons, Orions, and Meades, whose refractors are not available in Japan, and the resellers will not ship here. Always very annoying: I want to give them my money, but they won't let me.)

What it doesn't need to be:
- Chroma-free/super duper triplet APO fluoride for pin-sharp awesome stars. Anyway with the budget above kind of excludes those. I already know that I will not have the time for a while to do extremely serious AP, but some nice wide-field images would be nice.
- from a renowned manufacturer

From my research, I am looking at the below:
- Orion Shorttube 80: there probably is a way to find those in Japan, and it is very cheap. Would it let me take OK widefield pictures? Again, I don't really mind if the stars are not super pin sharp, or have some coma.
- Takahashi FS-60CB: I can actually buy this one in Japan with dovetail at a reasonable price of 800 USD. Of course the temptation here is to own a Tak, but I really just want to get the best bang for the buck
- Mini Borg 60ED: this one with and optical back is around 600 USD here in Japan. Very small, very cute, and very tempting
- William Optics: Zenithstar 71 Doublet ED APO for 500 US shipping included is very very tempting.

Otherwise, I could go a completely different way and get the cheap (250 USD with dovetail) Orion StarBlast 4.5 Imaging Reflector Telescope Optical Tube, because it is light, and just 45 cm long. It also has the best focal ratio of the lot. What would I lose compared to the above more expensive refractors?

Thank you!!

Yannick

#2 Jon Isaacs

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Posted 25 April 2013 - 05:33 AM

Yannick:

What camera are you using? Matching the scope to the camera is important. If you are investing real money in a scope, getting the best match would be in order.

People do use ST-80s for imaging but the chromatic aberration is always an issue and in any event, the focuser and such is not really of photographic quality. Of those you mention, to my eye, the William Optics Zenith Star is the most attractive though with a DSLR sized chip it would ideally be used with a field flattener.

Jon

#3 RogerRZ

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Posted 25 April 2013 - 08:22 AM

Given your budget, I'd go for a ZS71, and I think for $200, you could easily find the flattener that John mentions, especially if you scour the used market (I paid $100 for a WO FLAT-2 that does a decent, if not perfect job). This would give you a scope with capabilities that will likely exceed those of most beginners for quite a long time.

#4 cuivienor

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Posted 25 April 2013 - 08:41 AM

Thank you very much for the feedback - the ZS71 indeed seems like the best that I can get.

To answer Jon's question, I'm planning to use my Meade DSI II Pro Mono and occasionally my Sony NEX-5 mirrorless.

The FOV on the DSI should be pretty small, my guess is that at first I wouldn't need a field flattener.

Also this is my very first time buying a refractor, of any type. With such a short focal length, would a finder be absolutely necessary? I am quite amazed by how expensive just the finder rings are! I'd probably go for a simple red dot finder.

Thanks again for the tips.

Yannick

#5 snommisbor

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Posted 25 April 2013 - 09:03 AM

With a scope of that size you could start out unguided and get easily 60 second shots and maybe even longer depending on your mount. I started out with a WO Megrez 80 unguided and got some pretty great shots

#6 RogerRZ

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Posted 25 April 2013 - 10:18 AM

The DSI chip is a bit more than half as big as the chip on my ST2000, so you might be able to bypass the flattener, but "just". Corner stars will likely still be a bit wonky.

#7 Astronewb

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Posted 25 April 2013 - 12:08 PM

Yannick, if you live in Japan, then the Borg 60mm would be the best bet for you on the SmartEQ Pro. If you have the polar scope aligned to the mount axis, it will easily give you 2-4 minute unguided exposures.

The Borg 60ED is super compact and light,and there are tons of accessories available for it in Japan, flatteners, reducers, etc.

These are some images I have taken with the Borg and SmartEQ Pro:

Posted Image
M42, B33 Final w/Borg 60ED by Astronewb2011, on Flickr

You can also find on my Flickr page some easy mods to make on the SmartEQ mount/tripod to really make it suitable for AP.

Good luck, looking forward to some images from Tokyo.

Paul

#8 cuivienor

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Posted 25 April 2013 - 08:41 PM

Thank you all for the opinions.

This is a very impressive picture taken with the Borg - the 60ED indeed is extremely light and small from what I can see...

Such a tough choice! The William Optics is definitely the cheapest (besides the Shorttube which is not really suitable for AP), and let's be honest, the prettiest too.

I'm just very confused about the very modular Mini Borg, but I'm catching up onto it.

I will however wait until I can confirm that my smart eq works! For the moment, it came with a defective controller!!

Yannick

#9 WarmWeatherGuy

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Posted 26 April 2013 - 12:25 AM

Have you looked at the AstroTech AT72ED?

If your chip size is 6.24 x 5.01 mm then your field of view will be 50' x 40'

It is 30cm long when folded up in its 40cm carrying case. It is around 4.5 kg (scope and case together).

#10 cuivienor

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Posted 26 April 2013 - 03:14 AM

Thanks Steve for the recommendation - it does look absolutely great as well (but on waiting list...)

So now I am at:
- AT72ED
- Borg 60ED
- WO ZS71

Or even the Starblast imaging OTA...

So conflicting! Will mull over the week-end...

Yannick

#11 WarmWeatherGuy

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Posted 26 April 2013 - 07:51 AM

Yes, it is on the waiting list. The AT72ED comes in many different colors and they are all on the waiting list except for pink. The pink scope is available now. You will have to wait for white, black, green, red, and blue.

#12 nine44

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Posted 26 April 2013 - 08:15 AM

Just a word of caution on the Starblast--if I recall--it is intended more for small chip AP--you may experience vignetting with your Sony NEX camera.

#13 MooEy

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Posted 26 April 2013 - 05:32 PM

if you are planning to do imaging, it better have a flattener/reducer for it. the borg 60ed has the option of either the #7885 and the #7870.

and when you are bored of imaging, the 60ed serves as a very nice finder...

~MooEy~

#14 Momerath

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Posted 26 April 2013 - 07:05 PM

+1 on the At72. or you could roll for a AT65edq. Next shipment is in july

#15 Ziggy943

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Posted 26 April 2013 - 07:21 PM

Yannick, if you live in Japan, then the Borg 60mm would be the best bet for you on the SmartEQ Pro. If you have the polar scope aligned to the mount axis, it will easily give you 2-4 minute unguided exposures.

The Borg 60ED is super compact and light,and there are tons of accessories available for it in Japan, flatteners, reducers, etc.

These are some images I have taken with the Borg and SmartEQ Pro:

Posted Image
M42, B33 Final w/Borg 60ED by Astronewb2011, on Flickr

You can also find on my Flickr page some easy mods to make on the SmartEQ mount/tripod to really make it suitable for AP.

Good luck, looking forward to some images from Tokyo.

Paul


Very nice :)

#16 cuivienor

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Posted 26 April 2013 - 09:10 PM

Thank you all for the recommendations (and beautiful picture with the Borg).

So what I see up to now:

1. AT72ED

Pros:
- available on Astronomics
- Combo with the AT reducer/flattener makes in 500 USD + shipping (around 150 USD I guess).
- Small size, proven astrophoto ability.

Cons:
- On waiting list, except for the pink one
- needs to ship from the US

2. Borg 60ED

Pros:
- Extremely light and small
- Can be used as a finder
- Lots of support in Japan, no need for international shipping. Warranty is therefore easy.

Cons:
- Expensive: astro set plus reducer/flattener brings is to 900 USD, very much over budget
- Complex: honestly slightly lost by the bewildering list of accessories, connectors, etc.

3. WO ZS71ED
Pros:
- Available immediately
- 500 USD including shipping
- Comes with 1.25 diagonal
- very pretty :)

Cons:
- Reducer/flattener currently only available in the US. Adds 200 USD to the price if I can find a way to get it
- International shipping, questions about warranty


So right now I am leaning towards the AT72ED: good quality, cheap, etc. I assume that basically the optical quality of each is roughly identical (although optical attributes aren't).

Now my question is: if these scopes require field flatteners. Why isn't that element integrated it, or at least kits available from the manufacturers?

Thanks again for all the advice, and pointing me to the AT72ED.

Yannick

#17 WarmWeatherGuy

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Posted 26 April 2013 - 09:15 PM

If you're using the Meade DSI-II you may not need a field flattener. The chip is small enough it may not extend out to where a field flattener would be noticed. I would hold off getting the field flattener until you take some pictures without it. If the stars in the corners are still round then you don't need one.

#18 olivdeso

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Posted 26 April 2013 - 09:19 PM

I would rather choose a Japanese refractor, the FS60 would be my first choice. The Borg FL71 my second.
Both are made of canon fluorite glass. State of the art lenses. Just in another league compared to the other refractors of the list.
They are doublets with a little bit of longitudinal chromatic error, but this error is reduced using the dedicated flatener.

Here you can find a detailed report of the FS60 (it is in french, but you can google translate, or simply have a look to the pictures and graphs)

http://www.airylab.c...-42001-v1.2.pdf

http://www.airylab.c...article&id=4...

Also these refractors have tons of astrophotography dedicated accessories, which is very usefull. The FS60 has a very interresting reducer which offer a wide field and fast focal ratio.

Here you can see some nice wide fields made by a guy in the south of France, in a dark place, using the FS60 and a DSLR. (APS-C sized. larger sensor would require a new focuser)

http://www.flickr.co...oto_en_ardeche/

That said, my prefered small refractor is the 80/480 FPL53 triplet which is available from many brands (astroprofesionnal, orion, TS, Altair and else. There is another brand in Japan, but I can't remember what it is...) with either aluminium or carbon tubus. I had 2 from TS, both had excelent optics. Extremly low longitudinal chromatism (i.e. perfect for color sensors) and well figured (polystrehl higher than .95). The tube is very small, close to the FS60.

I would also consider the skywatcher equinox if it fits in the budget, because it is really excelent (FPL53 doublet, well manufactured). I will be better than the FPL51 or equivalent doublet mentionned in the list.

There is another tube that might interrest you : the Lacerta 72 FPL53 doublet. It is the same tube as the WO72 but has the FPL53ED glass. Have a look to the test pictures here: (there are some other in the test section of Teleskop Austria website. You can also visit Wolfgang Rohr's website, there are a lot of test reports)

http://www.teleskop-...kod=rapo-072...

enjoy!

Olivier

#19 cuivienor

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Posted 28 April 2013 - 06:06 AM

Hello,

I just wanted to give an update on this.

While visiting an astro shop in Tokyo this Saturday, I came across a Sightron Japan 66ed scope for 400 USD, and was so stunned by its beauty I got it on the spot (couldn't get the demo item, had to order one). It basically seems to be a rebranded version of the AT66ED.

No shipping, reasonable price, small and light, exactly what I wanted. Olivier and all, thank you very much for all your help: in the end the taks and borgs were too expensive and in the end the rebranded Astro Tech won the day.


Will post a first light report once I get it!

Thanks again for all your help.


Yannick


PS: Olivier, thank you for all the links and your recommendations. In the end my budget was unfortunately too limited for your suggestions, especially in Japan. I'll always wonder why scopes in the US are so often twice as cheap as in France or in Japan...

#20 cuivienor

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Posted 01 May 2013 - 02:33 AM

One further update on this - in the end the Sightron didn't work out - I have therefore ordered a refurbished refractor from the Japanese Kasai Trading brand, the Blanca-70ED with the Kasai low-profile DX microfocuser.

Aperture 70mm
Focal length 420 mm (F6)
1.9 kg
transport length: 29 cm

Anyone has heard of that brand before? They seem very "Takahashi-tish" to me.

http://www.kasai-tra...blanca-70ed.htm

Will report back once I actually get it.

Yannick

#21 james7ca

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Posted 01 May 2013 - 03:03 AM

I have an AT72ED and for wide-field photography I use it with a Sony NEX-5N camera. Given the Sony's APS-C-sized sensor and 16 megapixel resolution you will definitely need a field flattener to make use of anything more than the center 2k-by-2k image area. If you decide on the AT72ED then you might want to get the recently introduced Astro-Tech 0.8X focal length reducer/field flattener.

I actually have both the standard Astro-Tech field flattener (1X) and the 0.8X reducer and for wide-field work I think the 0.8X reducer is the better option. However, even when using the Astro-Tech flatteners (either one) you won't get round, pin-point stars right to the corners of an APS-C format camera. This is where the 0.8X reducer helps, since you can crop off the "bad" edges and still have a relatively wide field of view (as well as more than a 1/2 stop increase in photographic speed, converts the f/6 scope to an f/4.8).

However, if your primary (sole?) purpose is wide-field astrophotography then you'd probably be better off with Astro-Tech's AT65EDQ.

#22 cuivienor

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Posted 01 May 2013 - 03:18 AM

Thank you very much for the further feedback.

Actually it seems my gear will be:
- Blanca-70ED
- Astro-Tech 0.8X reducer/flattener

Both are in stock and have been ordered.

I plan to use both my DSI II and my Nex-5 for pictures, as well as some light observing, so in the end, I prefer to have a scope ordered from Japan, with a Japanese manufacturer, at a lower price.

Hopefully with the Smart EQ Pro now fully functional, it will give me a great setup!

Next I will have to delve into Auto-guiding, but that is for much later :)

Yannick






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