Telescope advice

[Ukjonathan]

Hi again,

                I have got the chance to pickup a Altair Skywave 70ED and it’s in mint condition. It’s a perfect size for handling,transporting  around and home use for not a lot of money.  I must admit I really do like the Altair scopes build quality especially no plastic. I was also interested in the 102 but it is a lot more weighty although it’s another nice scope. I do though need to look at practicality especially with my disability.

Firstly, would this be a decent starter scope for  planetary viewing.? Also I own a Sony A5000 camera and I’m wondering what I’d need to attach it at some point to a telescope if at all possible. I don’t want to go down the dedicated scope cams fan assisted or cooler type even though I’m sure they are the Beas knees in camera for this sort of photography. Lightness and easy to use is all I need. I’m not expecting stunning pictures but more just to document my view. Again any help would greatly be excepted as my last mail was 

 

[Padraic M]

Hi Jonathan, there is a big difference between planetary observation and deep-sky objects (DSOs) like galaxies and nebulae.

 

The AA scope that you've referenced would be a very good starting point for DSO observation. It gives a relatively wide field of view with a focal length of 420mm, and is also reasonably fast at f/6. Scopes like this are very often used for general-purpose sky observation, and are ideal beginners' scopes. I have a similar 80mm f/5 scope that gets a lot of use. DSOs are often large, faint objects that need a moderate focal length, and a good aperture to observe properly.

 

On the other hand, planets are small and very bright! They prefer long focal length scopes and the aperture or f-ratio is not quite as critical. Many people would prefer a small Maksutov-type scope such as the Skywatcher Skymax 102 or similar for planetary observation. This has a focal length of 1,300mm at f/12.75 and is also small and portable.

 

Either is likely to connect to your camera for photography, but again, different techniques and processing is required for DSOs and for planets.

 

Astrophotography, particularly for DSOs, is a very slippery slope into a very deep rabbit hole, that requires good quality kit. Cooled cameras are preferred for DSO but are not required for planets. Heavy, autotracking mounts are needed for DSO, but not so much for planets.

 

Longer-focal-length scopes tend to be harder to use, especially for beginners, but if you are intent on observing planets as your priority, a Mak may be the solution. However, the AA 70ED will also show you the planets - especially if you use good quality high-power eyepieces - so it's not at all a bad way to go as a starting point.

 

HTH

[Nightspore]

I'm not familiar with that scope. Is it like this? I'm not sure who actually manufacture Altair refractors, although there are probably equivalents sold under other names. 

 

It would help if you knew the focal length and focal ratio. If it's around f/6 and a 420mm focal length it's very similar to my 72ED Evostar. In which case you should be able to get between 100x and 140x fairly easily. Although you'll almost certainly need to use a Barlow lens. GSO 2x Barlow

 

Then you can use something like a 6mm Plossl to achieve 140x. Of course, magnifications depend on conditions. Although, unlike most reflecting scopes, you may be able to push even higher on targets like the Moon with a decent ED refractor. 

 

I've had 200x with my 72ED on the Moon in very good conditions and when it was high. 

[Nightspore]

15 minutes ago, Padraic M said:

Many people would prefer a small Maksutov-type scope such as the Skywatcher Skymax 102 or similar for planetary observation. This has a focal length of 1,300mm at f/12.75 and is also small and portable.

 

 

 

Personally, I prefer my 72ED Evostar to my 102mm Mak' for planetary as a refractor will always be sharper. There is no obstruction in a refractor and this aids contrast. For small apertures  especially, I'm pretty convinced that acuity and contrast trumps aperture size every time. I regularly see better detail with the 72ED over the 102mm SkyMax. Furthermore, a refractor can be pushed far more. Magnifications of 60x or 70x per inch of aperture are comparatively easy with a good ED refractor. It's not so easy on a Mak'. 

 

 

I’m a bit ambivalent about comparisons between small refractors and Mak's. The 102mm Maksutov effectively has a limiting magnitude of 12.74 compared to the 11.99 of the smaller 72mm ED doublet. I can often reach around 140x with either of them for planetary observing.

 

 

I personally prefer the visual acuity and contrast of the smaller refractor. The 102mm aperture has a Dawes limit of 1.14 arc seconds in comparison to the 1.61 arc seconds of the 72mm. The question is does 0.47 of an arc second and 0.75 of magnitude really make that much of a difference? These are basically backyard telescopes small enough to be carried in a flight bag. My 72ED gets used for planetary far more than my 102mm Mak'. I think it's a bit of a myth that 70mm refractors can't do planetary.
 

Edited July 31, 2021 by Nightspore

[Marmot]

AIthough I can’t add anything more concerning the suitability of the specific scope you refer to, I can thoroughly recommend Altair Scopes. I have recently acquired an Altair refractor and I was instantly impressed with the build quality and well thought out details. Several members of the yard have Altair scopes and I have never read a bad word concerning them.

[Ukjonathan]

Hi Nightspore,

                        Yes that’s the one but some of the fittings have been changed. It’s built nice though I’m tempted but did not know if I’d gain anything from an 80mm but I’m sure it would not be as better deal as this. I know one thing for sure the Skymax 127 I’ve got is now defiantly going up for sale. It’s a nice piece of kit but it’s too big for me to handle. Thanks all for the feedback appreciate it. It’s made me know what I’m going to do

Thanks to One & All

[Nightspore]

1 hour ago, Ukjonathan said:

Hi Nightspore,

                        Yes that’s the one but some of the fittings have been changed. It’s built nice though I’m tempted but did not know if I’d gain anything from an 80mm but I’m sure it would not be as better deal as this. I know one thing for sure the Skymax 127 I’ve got is now defiantly going up for sale. It’s a nice piece of kit but it’s too big for me to handle. Thanks all for the feedback appreciate it. It’s made me know what I’m going to do

Thanks to One & All

 

I don't think there will be huge differences between 70mm and 80mm refractors. The ratio would be that the 80mm would have a 1.31 better light grasp.

 

The 80mm would have a limiting magnitude of 12.22 compared to 11.93 of the 70mm. Which means that the 80mm will only have 0.29 of a magnitude greater advantage. 

 

The 80mm will have 0.21 of an arc second better resolution than a 70mm for planetary observing. These aren't massively noticeable differences IMO.

 

I've seen planetary transits on Jupiter with a 60mm Altair refractor.

 

 

Furthermore, the 70mm Altair refractor should be able to take 2" and 1.25" diagonals. The 127mm Mak' probably doesn't have a 2" visual back. Mine doesn't, although I think they can be fitted. 

 

A 70mm ED doublet will be very versatile. You might have to use a Barlow occasionally, but a 4mm eyepiece will give 105x in a 420mm focal length. A relatively inexpensive TMB clone like this will give 131x.

 

 

Mak's are a bit specialist IMO, whereas a 70mm refractor will be much more versatile, let alone more portable.

 

The Altair refractor will have a much more precise focuser than the Mak'. I think it's a dual speed rack and pinion. Mak's are not good at precision focusing in my experience. You need the precision for planetary. You won't be disappointed with an Altair 70mm ED refractor. I can tell you that. 

Edited July 31, 2021 by Nightspore

[rwillits]

Sounds like a good choice. The Altair 70ED and your Skywatcher EQM35 Pro should be a good match for both viewing and AP (astrophotography). A DSLR is a good place to start. Many targets are available for a DSLR, like the Andromeda Galaxy, Orion Nebula, North America Nebula, M 78, etc.

[MarkAR]

As for the Sony

https://www.harrisontelescopes.co.uk/acatalog/sony-alpha-t-ring.html

plus either a 1.25" or 2" adapter to slot into the focus tube.

[Ukjonathan]

Hi thanks for pointing out the camera adapter and thanks to Nightspore for the recommendation 70mmED Doublet,  Saves buying wrong items until I learn more hopefully.

well I’ve defiantly narrowed down to two telescope the one I mentioned the Altair Starwave 70ED

or The  Altair Starwave 102ED. I like the build of these scopes somehow they seem to be engineered with thought. So I’m sorry to ask again but which one would you have out of them or get both? They seem better built than the Skymax I have 

[Nightspore]

7 minutes ago, Ukjonathan said:

Hi thanks for pointing out the camera adapter and thanks to Nightspore for the recommendation 70mmED Doublet,  Saves buying wrong items until I learn more hopefully.

well I’ve defiantly narrowed down to two telescope the one I mentioned the Altair Starwave 70ED

or The  Altair Starwave 102ED. I like the build of these scopes somehow they seem to be engineered with thought. So I’m sorry to ask again but which one would you have out of them or get both? They seem better built than the Skymax I have 

 

 

My Altair Starwave 102 ED-R OTA weighs 4kg without accessories.

 

 

Add a finder, diagonal, dew control and an eyepiece and it will push 5kg. The HAL 130 plus half pillar is at least 10kg. Luckily the TL-130 tripod can hold the 102mm ED-R fairly stable. A 5kg OTA with accessories will need stability. It's not a grab and go scope for me with my own disability.  I'm guessing the EQM-35 PRO would hold it. Bear in mind it's a kilo heavier than the 127mm Mak and physically longer.

 

 

So it needs a mount/tripod combination capable of holding it. An f/7, 10 centimetre refractor is larger than you realise. Personally, I'd get a 70mm (or thereabouts) refractor first and learn the sky with a light grab and go tripod/mount. 

[Ukjonathan]

Hi all just to let you know I finally got the Altair ED70 so I’m going to look for some main bits I’ll need for it and a cloudless night to try it. Thanks everyone especially Nightspore

[Nightspore]

10 hours ago, Ukjonathan said:

Hi all just to let you know I finally got the Altair ED70 so I’m going to look for some main bits I’ll need for it and a cloudless night to try it. Thanks everyone especially Nightspore

 

You're welcome. You know we expect pictures of the scope, right? lol

 

Have fun.

[Ukjonathan]

Hi well here it is especially for Nightspore. I was a full time illustrator and one of my clients wanted me to do him some illustrations this was part of the deal. Not as good as some of yours but it’s a start. I’m also getting a full spectrum SLR camera thrown in, but he said it was never fitted and would need some bits to fit it. He is dropping that off Sunday when he picks the artwork up. This belonged to his son who moved to Australia just over a year ago and did not want to take it.

enjoy

[Nightspore]

16 minutes ago, Ukjonathan said:

Hi well here it is especially for Nightspore. I was a full time illustrator and one of my clients wanted me to do him some illustrations this was part of the deal. Not as good as some of yours but it’s a start. I’m also getting a full spectrum SLR camera thrown in, but he said it was never fitted and would need some bits to fit it. He is dropping that off Sunday when he picks the artwork up. This belonged to his son who moved to Australia just over a year ago and did not want to take it.

enjoy

 

Looks nice. I have the WO bino as well. Bino's can have focusing issues with short tube refractors and you may need an extension tube. 

 

 

Mine don't really get out much.

[Ukjonathan]

Hi Nightspore, that looks like a nice array of eye pieces. I must admit I was more interested in the telescope. I’d like to give them a try at some point same with the camera but I would need the bits to join it to the telescope. Is an extension tube the same as a flatter? If so what size would I need? I’ve read that some fit 0.8x flatterers it that to allow to screw accessories on to the telescope  and also to adjust the magnification  ? 

[Nightspore]

25 minutes ago, Ukjonathan said:

Hi Nightspore, that looks like a nice array of eye pieces. I must admit I was more interested in the telescope. I’d like to give them a try at some point same with the camera but I would need the bits to join it to the telescope. Is an extension tube the same as a flatter? If so what size would I need? I’ve read that some fit 0.8x flatterers it that to allow to screw accessories on to the telescope  and also to adjust the magnification  ? 

 

I don't know anything about AP, I can only just about work the camera on my tablet lol. I only use my bino with my cat's. And they're slow.

 

 

As a consequence none of the EP's are particularly special and work well at f/8 or slower. Although I think the SWAN's work well up to f/5.

 

 

The 20mm SWAN's aren't the bundled WO eyepieces with the bino and I bought these separate. I have three nosepiece Barlows; both WO's and a 2.6x TS Optics. I'm not over impressed with the TS one. I don't use a field flattener. An extension tube is sometimes needed for back-focus although the WO 1.6x Barlow/glass path corrector bundled with the binoviewer should work instead as a Barlow technically increases the scope focal length.

 

 

The others are pairs of Altair (GSO) SuperViews, 12mm GSO Plossls and a couple of SvBony plastic fantastics. I have pairs of Astro Hutech (Ohi) orthocsopics as well and a few others but these are the current ones. I only really look at the Moon with them in my 127mm Mak.