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3 quick newbie questions


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Hi,

Just a few questions that have been niggling at me, hopefully some of you lovely people can assist me with my newbiness. :p

1. I am planning on buying a 130mm Dobsonian (Skywatcher Heritage 130p). I’m not sure how tall this is when mounted – do people tend to rest theirs on something, like a small table, or even use a tripod? It looks like it would be quite close to the ground.

2. I’m interested in solar observation and after I’ve had the telescope for a while I would like to get a solar filter. I’ve been reading up on safety information about solar observing, and I know not to get an eyepiece filter. I assume in my case, I would buy a 130mm filter (e.g. the Astrozap filter from FLO) which then fits over the whole sky-end of the telescope – is that right?

3. I’ve read around in a couple of places that the truss design of these telescopes makes them prone to light entering and interfering – is it necessary to block the light, and if so, can you use black card or fabric? I’ve seen the shrouds for sale but they’re a bit pricey for me and I’m hoping a cheapo DIY job would do the trick. :)

Cheers all!

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I think this picture of the 130P heritage should give you some idea of the overall size 130P Heritage. The overall height of the telescope is 695mm so some form of stand will be required to make viewing more comfortable. I would be looking for something solid that would bring the telescope up to eye level when sat on a garden chair. You may not be able to fit a commercial solar filter such as the Astrozap due to the shape of the top of the telescope where the focuser / finder / truss rods meet. You might be able to make you own out of Baader astrosolar film and stiff card.

Peter

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To answer your questions:

1. Yes you will need a table or stool. Due to it's size it will be to low down otherwise.

2. I personally wouldn't recommend looking at the sun with a dob, but if you have to then a full aperture mask is a must. Also blank of your finder just in case. Refractors are much better then dobs looking at sun, I've heard about secondary mirrors on dobs getting hot and even a few cases off them shattering.

3. A length of black cloth or card wrapped round will be fine. It just helps a little on contrast.

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Didn't know that about solar observation with dobs, thanks. It's something I won't be doing yet anyway, I'm just thinking ahead. I'll put that on hold for now. Run before you can walk, etc. :)

Thanks for the replies, very helpful as always! [removed word], I had little camping table that I left out in the rain and it warped. Would have been ideal. I'll keep an eye out at lidl and netto, they tend to do cheap garden and camping stuff sometimes.

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I have a Heritage 130p and as others have said you have to place it on a table to use it or kneel on the floor (not very comfy). In my opinion the scope has one or two issues firstly the truss design is not very sturdy and the weight of eyepieces can pull down one side of the top which puts the collimation out and secondly the secondary mirror is too exposed and the scope really needs a shroud but the focuser is partially in the way of fitting a shroud. If I were spending a similar amount of money again I would pay a bit more and go for a Skywatcher Skyliner 150, 1200mm focul length puts the ep at a much better height, larger mirror for better light grasp, solid tube design and its F8 so collimation will be a doddle. Just my 2 pence worth.

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Thanks, I'll have a think about that. One thing that drew me to the 130p was it's size, portability is a big factor for me - I'm only a small thing, plus I don't have a car, so I wanted something that would be relatively easy to carry about.

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It's fine to do Solar observing with a dob, as long as you use a full aperture filter.

Warnings about the secondary shattering only count when you are doing solar projection - this is why refractors tend to be used for this method.

Regards

Richard

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It's fine to do Solar observing with a dob, as long as you use a full aperture filter.

Warnings about the secondary shattering only count when you are doing solar projection - this is why refractors tend to be used for this method.

Regards

Richard

Great, thank you! Although looking again at the structure of the 130p, it does look a bit dodgy for fitting a filter to as Kris said, unfortunately. Might need to have a rethink.

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Hello Gytha Ogg and welcome to SGL.

That Dob you are considering seems to have thrown up a few problems! One that has not been mentioned yet is the fact that whatever you rest the instrument on needs to be SOLID. A wobbly (even very slightly) garden table simply won't do! Don't forget that you will magnify ANY instability in you mounting by the magnification you are using.

Have you considered the option of a small refractor? This one:

Evostar - Skywatcher Evostar 90 (AZ3)

Skywatcher Evostar 90 on either an altazimuth or equatorial mount with a tripod may well be a better deal - the price difference is neglegable. Portability will be no problem and you will not have to worry about collimation (the Dob's mirrors will need regular collimation). You can fit a solar filter far more easily too.

Hope this helps.

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Hi, that was very helpful, thank you! Thought I had made my mind up but it appears not!

When you say portability isn't a problem, would it be easy enough to carry about? I assume you don't just chuck it into a carrier bag. :)

I don't mean I'm going to be lugging it for miles on and off buses or anything, but I'd like to be able to carry it to local places. I don't have a car myself but the OH does so I would be able to bring (drag?) him along for longer trips.

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With a little 'scope like that the tube can be easily seperated from the mount/tripod and carried or transported by car. The Evostar i mentioned would be around a yard (or is that a metre?) long. The mount will collapse down to less than that. Another thought - tripods will work on ground that is not level - the legs are adjustable. The Evostar also gives an image that is the "right way up" using the diagonal - which makes it useable as a "daytime" telescope as well (The image in most astronomical telescopes is upside-down!)

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There are a couple of other small dobs made by Orion which are small like the Heritage 130p but they are both solid tube scopes. The first is a 4.5 inch scope and the second a 6 inch. Downside is they cost quite a bit more.

Orion StarBlast Astro Telescope - SCS Astro

Orion StarBlast 6 Telescope - SCS Astro

But having read what you said about wanting a portable scope if you went for the Heritage 130 I reckon you would be happy with it. Its a very simple but effective design that folds down to a fairly compact size and can be easily carried. It does not require a power source of any sort (other than human) and if you use it away from stray light sources and use eyepieces that are not too heavy you'll have fun. The scope maybe small but it will show you a lot.

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^ That's why I liked it initially, seemed about right for my needs, and solar observation can always come later - hopefully I can get a refractor too at some point. Solar was just an extra thing I was thinking of for the future - it's not the main reason I'm getting a scope. I've noticed you get more aperture to the £ with a dob too.

Thanks for all the advice everyone. :)

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