Getting Started advice...should I get a Dob?

[Goose0211]

Hi all,

Having dug out my dads 15 year old beginner telescope from the attic I realise things have moved on somewhat and am looking at getting started with a shiny new bit of kit.

Having been reading and reading it seems a reasonable amount of consensus points at getting a Dob as a great starter scope and moving on from their.  I’ve been looking at the SW Heritage 150p flex but am also drawn to the SW Explorer 130p or 150p as they seem to fit in my mind as sensible for use easily in the garden rather than having to find a flat surface for the Dob to sit on, and then crouch down to view (I appreciate larger and more expensive Dobs don’t require this!)  Am I right, or am I missing something with the Dob and it’s ease of use - surely I need a table, patio or other flat surface to use it properly?

Bang for buck I think I’m right in saying the Dob will give me a slightly better experience than the 130p and I think similar to what the 150p has.  At present I’m only looking to enjoy what’s up there and AP is not in my current thought process.

Any advice very welcome for a newbie to this.

Thanks

[wulfrun]

The advice would always be to go with the largest aperture you can afford and are comfortable with moving around. So the 150 beats the 130 either way, all other things the same. The Heritage collapses down to about half-size and has a tabletop mount, ideal for storage and very easy to transport. Yes, you are correct that you'd need a table or something to put it on unless you're happy doing yoga on the floor in the cold or damp. The "full-size" Dob (e.g SkyWatcher "classic") is free-standing, no table required.

A Dob is a decent starter and can last you far longer, depending where the interest takes you. As plenty of people on here will tell you, no one scope does it all.

EDIT: I've just realised you mentioned the Explorer, which is on an Equatorial mount. If you just want a point-and-look, an equatorial is not the easiest way to go. They require setting up to align with the north celestial pole and that's a faff for a beginner. Bear that in mind but don't let it put you off if you want to go that way.

Edited January 26, 2021 by wulfrun

[Orange Smartie]

Hi.  I've come back to astronomy after a long gap.  Originally I bought a smallish (4.5inch) reflector on a very heavy equatorial mount.  My new scope is a flextube 150p and I'm delighted with it.  Yes, you do have to put it on something, but you could use an upturned bucket, table or whatever - I have a triangular table my son knocked up for me.  It only weighs about 6 or 7kg, so it's dead easy to move outside when necessary and because the tube collapses, it doesn't need masses of space to store.  I appreciate it's not for everyone, but I love mine.  Plus, being a simple mount, it's very easy to point it at what you wish to look at, unlike the equatorial mount, which I found a bit of hassle. 

Pete

[Goose0211]

Thanks both, I think I’m edging in favour of the 150p dob and see how I get on. @Orange Smartiedid you get an additional lenses, a barlow maybe? Any recommendations?

Also need to find somewhere that has one in stock!!

[Orange Smartie]

The standard eyepieces are not all that great, which is what I was expecting. I bought myself a couple of BST starguiders and they are really nice - they have a bit that you screw out if you don't wear glasses, so that you can rest your eye directly on the eye cup - this works nicely for me as I tend to favour using the scope without specs, even though I'm a wearer.

If you go here:

https://astronomy.tools/

You can get an idea of how big your target will look based on the eyepiece you choose with the field of view calculator. So far I've got a 12mm and an 8mm eyepiece, which give me 63x and 94x magnification in my heritage 150p (750mm focal length). The eyepieces are about 50 quid each, with postage and came from first light optics and skies unlimited on ebay. I have a cheapo barlow 2x, but it's not great. May upgrade it at some point.

Edited January 27, 2021 by Orange Smartie

[Tiny Clanger]

Getting Started advice...should I get a Dob?

Yes.

[banjaxed]

My first scope was a 200p Dob and I still have it and would not part with it. I built a platform trolley for mine which enables me to wheel it out ready to go in 2 minutes. A water butt base is also a useful addition to raise the hight of the scope.

[Tiny Clanger]

OK, sensible reply !

Like Orange Smartie loves theirs, I love my little 150 heritage dob.

Fast to cool,  easy to store , easy to move, simple to set up, pretty robust , easy to use, £200 for a 150mm aperture , what's not to like ?! If you are thinking of the solid tube dob, do take the time to find out how big the things are, I decided against the solid tube due to not having much storage space, but the heritage closes down to about half length.

Some folk want to spend more, or have something more suited to taking photos through, or have guidance systems to steer the 'scope for them, but if you like simple stuff and a bargain , the answer is dob.  The heritage may need a table or box or stand of some sort to get it to a usable level for you, but it is a brilliant little thing. Obviously it has limitations, but the opportunities it gives greatly outweigh them for the price.

Having said that, there are folk on here who use the 130 newt. , who may have different perspectives to offer. I've used a 114 on a cheap EQ and flimsy bundled tripod and found the thing horribly wobbly and awkward. Unless you think you might want to go down the photo rabbit hole and want to spend hundreds on a really good EQ, I'd suggest if you don't go for a dob, at least choose an alt az mount which is simpler, cheaper and easier to use .

Every relatively cheap telescope package seems to come with some less than wonderful bits , quality skimped to get down to a price point, so skywatcher 'scopes come with a pair of eyepieces which can be , um, easily improved on , most folk reckon the included 25mm is OK, but the 10mm is not, and I'd agree with them. Also most folk on here say the BST starguiders are a good basic upgrade (at £42 each plus P&P if you go direct to Alan's website at Sky's the Limit , where he promises to be cheaper than his ebay shop of the same name) . I'd agree , either the 8mm or 12mm would be good replavcements for the stock 10mm .I also have the 25mm BST which is an improvement over the stock EP, but shows some flaws because of the focal ratio of this little telescope. (it is pretty good in my other 'scope though )

  If I was going to use just the heritage 150 (or the 150 solid tube, which has the same optics) I'd suggest you might consider buying a BST 12mm, a 32mm plossl ( skywatcher ones are about £30) and a 2x barlow (for around £25 last time I looked.) That would give you a 32mm, 32mm plus barlow = 17mm ,12mm BST and 12mm BST + barlow = 6mm which would probably be the greatest useful magnification in most UK sky conditions (I'm assuming you are in the UK ... )

The other less than adequate accessory in most 'scope packages is the finder , but I think it is best to worry about that when the shortcomings of the supplied red dot finder become apparent to you.

Heather

 

[wulfrun]

2 hours ago, Goose0211 said:

Thanks both, I think I’m edging in favour of the 150p dob and see how I get on. @Orange Smartiedid you get an additional lenses, a barlow maybe? Any recommendations?

Also need to find somewhere that has one in stock!!

The solid-tube Dob 150P is an f/8 scope and the Heritage is an f/5. At the risk of patronising you if you already know this but this means the solid-tube has a more limited maximum field of view (FOV) BUT it is less demanding on eyepieces, so you can get away with cheaper ones.

With a 32mm plossl, for instance, the solid-tube gives a FOV of about 1.3 degrees at x38 magnification, the Heritage gives 2.2 degrees FOV at x23. Nearer the other end, a typical 8mm (say a BST, 60-degree) in the solid-tube gives FOV 0.4 degree at x150 and the Heritage gives FOV 0.64 degree at x94.

The upshot is that the Heritage is better suited to wider-field targets (DSOs etc) whereas the solid-tube is better suited to small targets (planets/lunar and double-stars etc). Worth thinking about.

Also worth thinking about as a first lens purchase is a zoom. Not everyone likes them but I do (so far!) and many others love them. There's a cheap-as-chips SVbony 7-21mm, the slightly more expensive OVL Hyperflex 7.2-21.5mm or the - fairly expensive - Baader Hyperion 8-24mm, amongst other choices. Any of those will perform well in the solid-tube 150P and at least adequately in the Heritage. The SVbony is so cheap you can use it as a kind of "disposable" to find out what focal lengths you will use the most; then purchase fixed ones if you want. Downside of zooms is their narrow field of view at the longer settings, which is not ideal. For longer though, the 25mm that comes with the scope is tolerable for a while - or the abovementioned 32mm plossl isn't expensive.

Just some things to think about, at the end of the day you pick what you feel is best.

Edited January 27, 2021 by wulfrun
Goofed the FOV/mag figures!

[Tiny Clanger]

7 minutes ago, wulfrun said:

The solid-tube Dob 150P is an f/8 scope and the Heritage is an f/5. At the risk of patronising you if you already know this but this means the solid-tube has a more limited maximum field of view (FOV) BUT it is less demanding on eyepieces, so you can get away with cheaper ones.

 

Ah. my mistake, sorry : I thought I recalled seeing they had identical optics, but what it actually says on the FLO heritage page is

"The Heritage-150p is easy to use and has the same Parabolic Primary Mirror as the highly acclaimed Explorer-150P so provides wonderful views of the Moon, planets and the brighter Deep-Sky Objects. "

https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-az4-mount.html

[wulfrun]

1 hour ago, Tiny Clanger said:

Ah. my mistake, sorry : I thought I recalled seeing they had identical optics, but what it actually says on the FLO heritage page is

"The Heritage-150p is easy to use and has the same Parabolic Primary Mirror as the highly acclaimed Explorer-150P so provides wonderful views of the Moon, planets and the brighter Deep-Sky Objects. "

https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-az4-mount.html

Confusing isn't it. There's the 750/150 [f/5] in the Heritage (Dob) the Explorer's OTA and the 150PDS but it's 1200/150 [f/8] in the Classic (Dob) and 150PL (OTA). At least, I think that's right!

Edited January 27, 2021 by wulfrun

[Carl Au]

On 26/01/2021 at 20:00, wulfrun said:

The advice would always be to go with the largest aperture you can afford and are comfortable with moving around. So the 150 beats the 130 either way, all other things the same. The Heritage collapses down to about half-size and has a tabletop mount, ideal for storage and very easy to transport. Yes, you are correct that you'd need a table or something to put it on unless you're happy doing yoga on the floor in the cold or damp. The "full-size" Dob (e.g SkyWatcher "classic") is free-standing, no table required.

A Dob is a decent starter and can last you far longer, depending where the interest takes you. As plenty of people on here will tell you, no one scope does it all.

EDIT: I've just realised you mentioned the Explorer, which is on an Equatorial mount. If you just want a point-and-look, an equatorial is not the easiest way to go. They require setting up to align with the north celestial pole and that's a faff for a beginner. Bear that in mind but don't let it put you off if you want to go that way.

An 150p and an AZ4 is a much better bet. Very comfortable to use. Definitely a step up from a 150 dob, if you can actually find one for sale like...

[Goose0211]

Thanks all. 

People mention eyepieces which are better and some that aren’t.

Is it a one fits all scenario with eyepieces or is there something I need to look out for in terms of what will fit the 150p FlexTube?

[wibblefish]

42 minutes ago, Goose0211 said:

Thanks all. 

People mention eyepieces which are better and some that aren’t.

Is it a one fits all scenario with eyepieces or is there something I need to look out for in terms of what will fit the 150p FlexTube?

In terms of fit as long as you get the right body width for the diagonal then they will all fit i.e. 1.25" vs 2" (I am guessing the 150p will be a 1.25").

In regards what you want them for there are the choice is endless as a variety of different eyepieces that do different things (i.e. wider angles, more magnification etc.) as well as provide different levels of "eye-relief" (i.e. how close you have to get your eye to it to achieve a full viewing angle. Usually you need to select a combination of eyepeices at different focal lengths to achieve wide field vs close up. Some people will also recommend a "zoom" lens which means you don't need to keep swapping len's and could be useful if you aren't quite sure what magnification you want.

The standard ones supplied with most telescopes seem to be a 25mm (wide) and a 10mm (close up), in my telescope (sky-watcher) the 10mm was a bit poor but the 25mm was fine but neither had good eye relief (I couldn't use my glasses for example if I wanted to, the 25 was ok but the 10mm was very bad in this regard).  That said I would suggest you see how you go before upgrading but if you do want to upgrade there will be plenty of people on here who can recommend certain ones / brands.

I eventually replaced mine with a BST Starguider set of 25 / 18 / 12 which are often recommended and the step up in eye relief and quality was very large.

There is a thread below which can help on deciding the right lengths and there is a Field of View calculator (you plug your telescope measurements into) which can show you the differences between eyepieces on various targets for an idea.

 

Edited January 28, 2021 by wibblefish

[Zermelo]

To take your question very literally, then of course you need eyepieces that fit your focuser, which I assume is 1.25".

But I presume you're meaning whether eyepieces that are good (or bad) for one scope are the same in others, and the answer is "not always".

So, if you spend £400 for a very well designed EP then you can expect that it will perform as well as anything could in your scope, i.e. it's not adding any aberrations to the images that were not already there in the first place.

But it's also true that some cheaper eyepieces can perform better in some scopes than others. In particular, EPs that offer wider apparent fields of view (say, 60 degrees plus) sometimes struggle more with "faster" scopes (i.e. shorter focal ratios) than on "slower" scopes. Your dob is one of the faster designs, so there are some EPs that will add distortion to the image (especially at the edge of the field).

If you're looking for EPs at a reasonable price (subjective I know) that are known to perform well in scopes like yours, then have a look here, or for a narrower field there are these, and this zoom is known to perform well too. 

[Tiny Clanger]

On 27/01/2021 at 17:53, Goose0211 said:

Thanks both, I think I’m edging in favour of the 150p dob and see how I get on. @Orange Smartiedid you get an additional lenses, a barlow maybe? Any recommendations?

Also need to find somewhere that has one in stock!!

Be very quick , go to this page, click on the link there ...

https://stargazerslounge.com/topic/371156-sky-watcher-classic-150p-dobsonian/

If you get page 404 , you were too slow.

Heather

[Tiago Ferreira]

go for a dob. the bigger you can. later you upgrade to...a bigger dob!