Astroscope + DSLR = Setups! (1 Viewer)

[Tord]

Tord,


...

I see your mount is shortened. Do you just flip the hood over then? Or at least could you?

http://www.e-group.uk.net/gallery/data/1243/IMG_4739_DxO.jpg

Frank,
This is the SW80 as delivered, I have not done anything except replacing the dovetail that came with the scope with a Giotto plate and wrapped the scope in camo tape.

/Tord

 

[JGobeil]

Thanks Paul,
... Also, i checked the scope again for interior reflections. Though the tube is flocked, the focuser is not. I'll have to fix that! ...

May I suggest you be careful playing with the focuser. Many people think (I was one of them) that there are no collimation problems with refractors. The front cell, the focuser and the diagonal (if you use one) must all be aligned. It seems that focuser mis-alignment is the source of 90% of the problems with refractors.

I suspect this is the problem I have with my Astro-Tech 550-80ED. The focuser was slipping and I wanted the fine tuning knob to be on the left hand side. I fixed both but I probably mis-aligned it.

 

[Miles Green]

May I suggest you be careful playing with the focuser. Many people think (I was one of them) that there are no collimation problems with refractors. The front cell, the focuser and the diagonal (if you use one) must all be aligned. It seems that focuser mis-alignment is the source of 90% of the problems with refractors.

I suspect this is the problem I have with my Astro-Tech 550-80ED. The focuser was slipping and I wanted the fine tuning knob to be on the left hand side. I fixed both but I probably mis-aligned it.

Aaah, thanks for the warning! Maybe i won't touch it then!

 

[JGobeil]

... The minimal length would be:
404 mm + 30 mm + ~5 mm = 440 mm
The 5 mm come from a plug the end to avoid dust.

Note that since it is wrapped in camo tape one detail is not clearly visible and that is where the tube ends and where the front hood starts. Look at picture #1 and you get an idea where it fits. The front hood is easily un/mounted. One detail: the front cap that comes with the scope is designed to be fitted on the front of the lens hood. So you will have to fabricate one, which should not be too difficult, perhaps out of a 4" PVC pipe ending, shaping it with heat air gun for good fit to the tube. This will add another few mm. ...

Hi Tord,

Here is the answer I got from the dealer I'm planning to purchase it from:
"... 23.5" in length with the focuser racked in. The lens shade is not retractable. It can be removed but there is nothing to cover or protect the objective lens if you do that."

23.5 inches with lens shade match your measurements and it is ok with my backpack as long as I detach the hood.

If I make a protection cap, which should be quite easy, will it sit right on the lens or is there some sort of protection ring around it ?

I wish there was a dealer close by with one in stock !!! Could you post a photo of the scope end without the shield ?

Thanks
Jules

 

[emilhugo]

Hi Tord,

Here is the answer I got from the dealer I'm planning to purchase it from:
"... 23.5" in length with the focuser racked in. The lens shade is not retractable. It can be removed but there is nothing to cover or protect the objective lens if you do that."

23.5 inches with lens shade match your measurements and it is ok with my backpack as long as I detach the hood.

If I make a protection cap, which should be quite easy, will it sit right on the lens or is there some sort of protection ring around it ?

I wish there was a dealer close by with one in stock !!! Could you post a photo of the scope end without the shield ?

Thanks
Jules

Jules,

I will be doing exactly the same as you do - removing the dew shield and making a DIY protection cap. I was looking for an image of the front, the lens element as well and found this one here:

http://ioannis21observatory.blogspot.de/2009/09/blog-post.html

I think it's fairly obvious that the crown glass sits a fair amount back in the lens cell body. So no protruding and the risk of scratching the lens.

Tord changed the dovetail to a shorter one so it might be possible to make some (permanent) modification to the shield to make it retractable.

Just have to wait a couple of days more as my SW80ED is now being selected, tested and collimated before being dispatched. :gh:

Have fun with yours!

Frank

 

[punta]

I have the Celestron version of this scope. The glass does not sit that far back when you take the shield off, so be careful you do not scratch the lovely glass

see photo

 

[Tord]

Hi Tord,

If I make a protection cap, which should be quite easy, will it sit right on the lens or is there some sort of protection ring around it ?

I wish there was a dealer close by with one in stock !!! Could you post a photo of the scope end without the shield ?

Thanks
Jules

Jules,

I am afraid I will not have access to the scope until Wed or Thu this week.

Meanwhile, to give you an idea:
The tube is ended with a thread.
The front lens assembly is secured at the front of the tube by a quite massive threaded ring that has an exterior "seating" at the front.
The ring is shaped so that its external diameter is same as the external diameter of the hood, and the diameter of the groove is same as the inner diameter of the hood. The depth of the seating is about one centimeter, about perfect to firmly hold the hood in place, yet possible to remove it. (The hood has a thin layer of some felt-like material to create the friction.) The difference of diameters is around 4 mm (hood is about 2 mm thick aluminum)

There is no external thread on the ring.

The front cap (plastic made) that comes with the scope will not fit the front ring, so you need to fabricate one.

What you could do:
Saw a thin slice of the lens hood, about two cm thick, just enough to keep the front cap in place. For good fit you may need some inner lining using felt/flocking material.
Fabricate one from some plastic. I was thinking about ending for PVC piping, final fit to be given using thermo-gun and/or electric tape.

 

[JGobeil]

Thank you gentlemen. Your help is much appreciated. I can't understand why the designers didn't make the hood retractable... it would have been just as easy. I'll have to find a solution as this empty tube will take too much valuable real estate in my backpack.

 

[Tord]

Thank you gentlemen. Your help is much appreciated. I can't understand why the designers didn't make the hood retractable... it would have been just as easy. I'll have to find a solution as this empty tube will take too much valuable real estate in my backpack.

Jules,
I believe this is a dliberate design and also to save costs, the original application area for this equipment is not portable terrestrial photography, I guess that transportation/storage is of second concern for astronomy.

The scope was delivered to me in a long box, with the hood and cap fitted.
/Tord

 

[emilhugo]

Tord, did you have your 80ED collimated after you bought it?

I ordered from a vendor who checks every scope before shipping it out.
Do you just don't care or do you trust that the manufacturer did his best in optimization?

I'm just curious..:cat:

 

[Paul Corfield]

I've had my lens cell off loads of times, I've taken the glass out of the cell to clean it loads of times, I've had the focuser off a handful of times, stripped it down for cleaning etc. Still works perfectly.

A doublet will rarely need any special collimation at the lens end because they aren't sensitive to collimation errors. If they needed collimation then the provision to do so would be provided such as you get with a triplet.

The only thing you really need to be sure of is that your focuser is running true. A Cheshire eyepiece will let you know if it isn't properly aligned.

Paul.

 

[Tord]

Tord, did you have your 80ED collimated after you bought it?

I ordered from a vendor who checks every scope before shipping it out.
Do you just don't care or do you trust that the manufacturer did his best in optimization?

I'm just curious..:cat:

No.

I had the scope sent back just after purchase to have the lens cleaned, there was also lose paint fragments inside. (Teleskop Service fixed it promptly). This was before Paul told me I could easily have fixed it myself. Since then I have taken off the front lens twice for cleaning dust, tightening the focuser a few times and I have not seen any issues with misalignment.

 

[cango]

me too. pulled it apart several times, drilled holes in it, even drop it - hood hit floor first taking the punch... at least I can not see any fault with the optics.

 

[Tord]

Hello again!

So i got myself a telescope. Based on many recommendations (thanks everyboddy!) i decided on TS APO 80/500 super-APO triplet

...

Miles,

In your opinion, would the TS APO 80/500 be a good choice if looking for a scope that would be suitable for travel? Preferrably fit in a bag/rucksack that is accepted as hand baggage (or as a fallback in the suitcase and hope it survives...).

May I ask what the length of the scope is, with focuser and hood retracted? Is the hood easy to retract/extract? And what is the weight including the rings (but excluding the doveplate).

Other application areas would be used as complement to the SW80 600mm when long focal length can ce sacrificed for (more) portability and brightness. I for instance like to spot and photograph raptors, often in flight, and whenever possible try to use the car as hide and a shorter scope would be easier to operate with beanbag or window support.

Have you also tried it with a monopod, and handheld?

Kind Regards
Tord

 

[Paul Corfield]

This site has more specification info Tord. They list transport length with dew shield retracted as 355mm. Tube weight is 5.1 lbs, I bet with the rings it's still under 6lbs.

http://www.apm-telescopes.de/en/product.html?info=3905&x70b35=te6g9lukcj35pte5h61rhj6pp0

Paul.

 

[Miles Green]

This site has more specification info Tord. They list transport length with dew shield retracted as 355mm. Tube weight is 5.1 lbs, I bet with the rings it's still under 6lbs.

http://www.apm-telescopes.de/en/product.html?info=3905&x70b35=te6g9lukcj35pte5h61rhj6pp0

Paul.

Well that's what I went by, same info as the teleskop-express site. I'm a bit confused and upset about what they measured and weighing, as I expected something significantly smaller. Maybe there was some copy-pasting that went un-edited from the previous model? Maybe its because i know nothing about scopes and how they are measured? Anyway, this is what I measure:

- The scope measures 42.5cm with dew shield and focuser retracted, at max tube length (=with all of its removable "extension tubes" in place). You can make it shorter by removing the tubes.
- It weighs 3kg, including focuser and dew shield with max tube length, without the clamping rings. I don't know what weighed in at 2.3kg.
- The clamping rings weigh an additional 650 gr (including a 13cm aluminum arca-swiss style tripod plate. I forgot to remove it, sorry.) The telescope dove plate is heavy!
- the 50cm extender + 2''-to-T2 converter + dslr adaptor (pentax) + UV filter weigh 260gr.

It measures about 50 cm plus the dew shield in front of the camera (focused at infinity) an weighs 3.26 kg without the rings. If you really wanted, you could move the focuser forward to get the focuser knobs under the center of gravity, but it vignettes with the 2'' extenders i have.

So if you're planning of using this hand held.... and focus at the same time.... Hmmmm.... I don't think i'll be doing it with mine.

With a monopod it's ok, though the position of the focuser (far back) makes me wish for a tripod.

With the tripod and gimbal, it's great, obviously. I have padded tripod legs and don't mind walking a mile with it.

By the way, the contrast is good now with the cardboard "diaphragm" and the UV/IR filter in place.

I know i haven't posted any pix yet. We have a heat wave here: put a long lens on a camera and one would think you're shooting though the exhaust fumes of a jet plane!

 

[JGobeil]

At last !

Well... I guess I tried everything to get decent results using my 2 scopes, the Pentax 80ED and the Astro-Tech 550/80ED. Not having any success, I decided to give up !

Well, not quite ! "Never say die"... so I purchased a SW80ED. I was able to get the scope at a good price without all the goodies that come with it: no EP, diagonal, mount, viewfinder, rings, case.

I made my own mount, using SS clamps with 3 layers of masking tape underneat to protect the tube finish and a home made aluminium bracket to attach the Arca-Swiss 17 cm plate. See photo.

There are some things I like about this scope and some I don't like. Lets start with the goodies: quite simple, it's cheap and sharp - that's all but it is what counts. I also like the finder socket on the focuser - it will be nice to attach a shotgun mike for videoscoping.

There are 2 things I don't like with the scope. First, the sun shield is not retractable - more on this later. It is also very heavy: it's made like a tank with a rolled steel tube and a cast iron focuser - including the home made mount (which is very light) and the plate, it weights 3.1 kg. Lastly, the 2" adapter does not have a compression ring - just 2 screws that scratch and mar the extender.

I can't understand why the sun shield has not been made retractable. IMO that's a big design flaw. It is also a very long beast to carry and store with the shield attached. To my great displeasure, I won't be able to use my Think Tank Glass Limo with it. Without the sun shield and extender, the scope is a tight fit but there is no room for the sun shield. Fortunately, I found a home for it and I will probably order a Lowepro Lens Trekker. Also, I think I found a way to make a perfect retractable shield at almost no cost - more on this in a couple of weeks - if it works like I think it will, you're in for a surprise !

I didn't didn't have a chance to go birding with it yet but I tried it in the backyard. I guess my confidence is back - there seems to be nothing wrong with my skills and my OM-D works at it should. Being manual focus and considering my eyes that play tricks on me, not all pictures have the same sharpness - but the good ones are quite sharp - see photo.

Using my 100-300mm lens as a standard for measurement, I get 550mm for the scope alone with the 50mm extender and 1100mm with the GSO barlow attached directly to the camera adaptor. Double these numbers for the crop factor and that's a lot of reach. I should get a bit more than 600mm with the extender attached but that's no big deal - or maybe the lens is more than 300mm ( 327+mm).

The attached photo was taken with the 2X barlow. It is a 100% crop of a RAW photo not processed in any way except for cropping and changing the profile to sRGB. ISO 800 - 1/2000 Sec - distance 70 m. - temp 28 C. This is the setup:
1. Oly OM-D EM-5
2. TelescopeAdapters True-2 M43 adapter
3. GSO 2X ED barlow screwed at the end of the camera adapter
4. 50mm extenter - the one that comes with the barlow
5. Scope

As you can see, I'm quite excited. I should have done that sooner.

Jules

 

[Paul Corfield]

I don't think the SW80ED is that heavy for a 600mm scope. A lot of the weight is at the front end as the lens mounting is a big lump of metal and glass. The tube itself isn't all that heavy.

Most shorter 500mm scopes with cnc machined bodies will be as heavy or heavier than the SW80ED.

Also if you think a 600mm lens from Canon will be almost double the weight of the scope so it isn't all bad.

The sun shield is best thought of as a dew shield and that's probably why they didn't bother making it retractable. The scope is for astronomy and when it's dark and the the air is cool you will always have the dew shield extended to minimize the glass from misting up.

If they went the extra expense and added all those features then it would probably have the lower quality FPL-51 glass to offset the extra manufacturing costs.

Look forward to seeing some photos from your new scope Jules.

Paul.

 

[cango]

As you can see, I'm quite excited. I should have done that sooner.

Jules

That's good to hear!

"I made my own mount, using SS clamps with 3 layers of masking tape underneat to protect the tube finish and a home made aluminium bracket to attach the Arca-Swiss 17 cm plate. See photo."

Interesting mod. Do you experience it to be sturdy?

 

[JGobeil]

... Also if you think a 600mm lens from Canon will be almost double the weight of the scope so it isn't all bad...
Paul.

There are many differences between the Canon 600mm II and the SW80ED.

1. 12,800US$ at B&H - 21 times more than what I paid for the scope, the extender and the adapter
2. f/4 vs f/7.5 - The SW80ED is almost 3 stops more
3. Auto focus
4. IS built in
5. 3.92 kg vs 3.2 kg with extender and adapter - the Canon is 22% more
6. 45 cm vs 61 cm for the SW80ED with extender and adapter - both measures without hood - the SW80ED is 36% longer
7. Tropicalized - dust and splash proof

Finally, IMO, there is not much difference between the best photos taken by you and a few others and those taken with the Canon.

Regards
Jules