what kind of telescope should i buy?

[Timebandit]

1 hour ago, swamp thing said:

Don't worry buddy. I actually own a 20" scope and it is not THE BENCHMARK for DSO's, to even suggest it is, is frankly ludicrous. There are a huge number of very successful deep sky hunters out there using far smaller kit. 

I also have a 10" scope just like yourself. It makes an excellent galaxy hunter. 

 

 

Fine . If it's so ludicrous why have all the dob mob got "Big Dobs" I take its just a man thing then "who has the biggest" ? nothing to do with the ability to resolve faint DSO better than smaller aperture's like 10" 

I take it swamp thing that you will be putting your 20" in the sale section soon on SGL and keep the 10" only as it's so good on DSO.

Just my opinion and must be ludicrous as all the professional observatory  I have seen and read about go for as much aperture as they can and quality mirrors for DSO. But what do I know☺     

[alanjgreen]

I'll stick with starsense thanks. as long as u are happy

For future reference, its probably worth noting that "solar system align" is the least accurate alignment available on the nexstar handset.

you will be more accurate using 1 star, and even more accurate if you use "auto 2 star", "3 star" is the most accurate but the most painful and time consuming.

From my experience, I would recommend you try "auto 2 star"

 

However, None of the alignments is as accurate as starsense (which uses 3 plates with up to 100 star matches on each plate)

[niallk]

15 hours ago, CavieVibesB33 said:

You say 20" is kind of the benchmark for dsos. I have a 10" and have become an avid galaxy hunter even with such as "small" scope. So my aperture fever is forcing me to upsize but a 20" is out of the question for me in terms of budget. I'm very interested in the Obsession 15". However there are the companies like Meade and Orion that offer a  16" at a much lower price. The Obsession has the better optics but would views at the eyepiece of a slightly larger 16" be brighter enough to make a difference? Or would I be better off with a 15" thereby providing slightly fainter images but with superior optics by comparison?

Hi CavieVibesB33,

I too have a 10" (a Skywatcher 250px - great scope - shows so much!!), and looked at upgrading to a ~16".  I ended up going for a 15".

I've never looked through a 16", but my best guess is that there a relatively modest difference (~0.14 mag, if I calc'ed right).

I'd suggest looking at the mechanical structures for stability, beautiful movement, holding collimation, portability - and very importantly how much hassle is setup and take down when you are tired.

Btw, I find the jump from 10" to 15" great! Of course, I lust for something bigger , but the 15" is good for me.

Best of luck,

-Niall

[mapstar]

19 hours ago, Timebandit said:

 

 

 

 

Hello. Hopefully the above diagram will help. In general for DSO especially it is the light gathering ability of the scope that you are after with quality mirror. Therefore a 16" will have the better light gathering ability in theory over a 15", but if the mirror is of low pv/strehl  on the 16" then you are better off going  with a 15" say  with a mirror of superior quality 1/10 pv/higher strehl IMO. But  If you owned  say a 15" scope of 1/4pv and a 16" of 1/4 pv then obviously you are better going with the 16" due to its increased light gathering ability. But in saying this if you already owned a 15"  scope then really you would want to jump to a 18" or more to make the extra expenditure a worthwhile to view exercise . 

By the way I own a 14" Orion Optics uk 1/10pv, and a very decent aperture for planetary and DSO , But as I commented already for serious DSO hunters then the bigger the better as the dob mob with their monster Dob reflectors prove time after time. Aperture Rules on DSO

I hope the above helps.☺

This makes interesting reading before getting hung up on wave front errors.

http://www.damianpeach.com/simulation.htm

Having delved into mirror making briefly I know very little about optics.

The most important thing I was told was the mirror can have whatever wavefront error you want but if it isn't smooth then you won't get a good image even before the atmospheric effects (which make the biggest difference) and other optical errors are taken into consideration.

Like I said though what do I know?. 

[swamp thing]

9 hours ago, Timebandit said:

 

Fine . If it's so ludicrous why have all the dob mob got "Big Dobs" I take its just a man thing then "who has the biggest" ? nothing to do with the ability to resolve faint DSO better than smaller aperture's like 10" 

I take it swamp thing that you will be putting your 20" in the sale section soon on SGL and keep the 10" only as it's so good on DSO.

Just my opinion and must be ludicrous as all the professional observatory  I have seen and read about go for as much aperture as they can and quality mirrors for DSO. But what do I know☺     

I cannot speak for the other guys (my friends) in the dob mob. But for me it's certainly not about setting any benchmarks. It's about inspiring others to get out under dark skies regardless of whatever aperture scope they have. Let us not get caught up in kit snobbery telling people whether or not their scope makes the benchmark lets just get out there and observe.  

No, I'm not selling my 20" Dob. The 10" is an excellent deep sky tool but the 20" is better. 

I hardly see a 20" Dob as a benchmark that any professional observatory would be seeking to compare itself too either.  

 

[ollypenrice]

There is no 'one scope for everything.' This image was taken with a little 85mm apo refractor.

If you really want to get involved in deep sky imaging you should do three things. 1) Stop reading manufacturers' advertizing immediately. 2) Read up on deep sky astrophotography, maybe starting with Making Every Photon Count by Steve Richards. 3) Browse, regularly, the deep sky imaging section of this and other forums to look at the images being produced and the equipment used to produce them.

Don't spend any money till you understand the imaging implications of focal length, focal ratio, pixel scale, autguiding and tracking precision. Imaging and visual astronomy have very little in common.

Olly

[BlueAstra]

9 hours ago, ollypenrice said:

There is no 'one scope for everything.' This image was taken with a little 85mm apo refractor.

If you really want to get involved in deep sky imaging you should do three things. 1) Stop reading manufacturers' advertizing immediately. 2) Read up on deep sky astrophotography, maybe starting with Making Every Photon Count by Steve Richards. 3) Browse, regularly, the deep sky imaging section of this and other forums to look at the images being produced and the equipment used to produce them.

Don't spend any money till you understand the imaging implications of focal length, focal ratio, pixel scale, autguiding and tracking precision. Imaging and visual astronomy have very little in common.

Olly

I love the 'this image was taken'. It hides the immense amount of skill and dedication expended in equipment procurement, site selection and processing expertise. Please Mr OP don't think you can get a result like this on your first night. Its a long learning curve but ultimately can reward you with results like this. Start simple and work your way up the ladder. As other posts have said, unfortunately visual and AP do not lend themselves to common equipment. Although a CPC and a wedge may sound like a good solution, you do not see many people using them, and the SCT has a long focal length that makes it difficult (though not impossible) to guide, and it has a slow F/Number for AP. A good start could be a CGEM with an SCT or Maksutov for visual and a short focal length refractor for AP on the same mount, either dual mounted or choose for the night. It would be a compromise, since you would get better visual with a Dob. But the best advice, as already stated, is to do your research and then try and make a decision. You may not get it right first time, but then who does!

[hubble space telescope]

first of all thank you very very much for your help!!!

second of all, i think maybe i will stay with the dobsonian telescope that i have (10 inch), and i will add to it a computer with the functions GO-TO and the synscan that allows the telescope to track after the objects. because after all, i understood from the forum is that i need to stay with the dobsonian because he is good as the cpc or the cgem in terms of light Gathering...

if you have any suggestions or Thoughts about my decision i will very glad!

and again, thank you very very much for your help  and the suggestions you was very helpful!!!!!!!!!!!            

[hubble space telescope]

thank you very very much!! you were really helpful to me and open my eyes to new suggestions!

but another thing, after all the answer that i read, i understood that maybe it's will be good to upgrade my dobsonian to a computerized telescope that will be able to him to do the functions like: GO TO, or synscan (that the telescope will track after the objects).  

because i understood that it will be good as buying a celestron telescope's (or at least will be more economical with high level of quality...)

and again, thank you very much and have continued a very good year!!!!!!!!!!

[hubble space telescope]

sorry about the two same questions, i thought that the first one was not sent...  

[Timebandit]

On 22/01/2017 at 16:38, mapstar said:

This makes interesting reading before getting hung up on wave front errors.

http://www.damianpeach.com/simulation.htm

Having delved into mirror making briefly I know very little about optics.

The most important thing I was told was the mirror can have whatever wavefront error you want but if it isn't smooth then you won't get a good image even before the atmospheric effects (which make the biggest difference) and other optical errors are taken into consideration.

Like I said though what do I know?. 

 

Hi. I do not get hung up on wave front error ect. But I just want the best quality mirror I can for the budget I have . And the times the atmosphere and seeing conditions allow for this mirror to come into its own and use the potential, then to deliver in those great seeing conditions with great views. Nothing wrong with wanting this is there?

I do planetary as well as DSO so my understanding of what I have read about mirrors is that a higher pv/ strehl mirror is more important and advantageous for planetary observing and detail. And for DSO a high pv/strehl mirror is not as important or such a factor .  

But obviously the all important factor if a high pv/ strehl mirror can produce it's potential is seeing/ atmosphere conditions.

But what do I know?

 

18 hours ago, swamp thing said:

I cannot speak for the other guys (my friends) in the dob mob. But for me it's certainly not about setting any benchmarks. It's about inspiring others to get out under dark skies regardless of whatever aperture scope they have. Let us not get caught up in kit snobbery telling people whether or not their scope makes the benchmark lets just get out there and observe.  

No, I'm not selling my 20" Dob. The 10" is an excellent deep sky tool but the 20" is better. 

I hardly see a 20" Dob as a benchmark that any professional observatory would be seeking to compare itself too either.  

 

 

I did not say a 20" is a benchmark for any professional observatory, A professional observatory will go for as much aperture and mirror quality as they can for DSO. But for a amateur wanting a serious DSO scope, wanting portability ,and a scope that will not put you in the bankruptcy court then a 20" "seems " to be the benchmark. But this suggestion was put down as ludicrous. So ludicrous to suggest this ,but most the dob mob have scopes around this size for there trips to dark site to use these 20" scope. Must of been a really ludicrous suggestions to make to the OP?

But as I have said what do I know.

 

OP ,have a look at the diagram i posted for you. As a picture is worth a thousand words and make your own mind up of what you prefer from the potential images available through different apertures(but maybe it was ludicrous so suggest this also)☺  

[alanjgreen]

hubble space telescope,

if you do decide to stick with the dob, then you have the option to modify it by adding encoders + motors (to create goto) or add encoders + nexus (astrosystems) to give "push to"

I am having nexus on my new dob as it creates a "wifi" and i can connect my ipad/skysafari software to directly see on the screen where the scope is pointing and use this info to find objects.

"push to" does NOT give tracking ability but "goto" (motors) DOES provide the tracking that you desire.

Anyway, here are some links

http://www.wildcard-innovations.com/

http://www.astrodevices.com/products/Nexus/Nexus.html

https://www.astrosystems.biz/drive.htm

 

All this will add weight and cost to your scope, so you may also want to consider buying a new "goto" truss dobsonian to replace the manual one you have. The one you have should be easy to sell and you don't have to mess about trying to upgrade it.

something like this...

https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-250px-flextube-goto.html would weigh less but I am not sure you could call it "portable" (but you know better than me what is too much or not?)

 

I assume you have given up on imaging?

If not, then you could stick with the dob you have for "visual" and buy an additional (1) small refractor or (2) 130mm newtonian imaging rig - but as said before, do buy "making every photon count" (you will know so much more after reading it)

https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html

You may notice that we all have >1 scope 

hope this helps,

Alan

 

 

[hubble space telescope]

wow!

thank you very much

im really appriciate all the answer guys!

thank you very much!

[niallk]

Hi Hubble,

I went down the road of adding Push-To and tracking to my manual solid tube 10". I added encoders (simple job !), and while I went down the route of Argo Navis (very pleased with it - use it on both my scopes), the WiFi Nexus sounds really great . Push-To is a worthy investment imho.

While I never felt the need for GoTo motors, I did yearn for tracking - I wanted this on planets with my 10". I found my 250px a little jerky with backlash and overshoot when operating manually at say 250x mag.  So, I purchased a tracking platform: it works, but tbh, I find I only sometimes use it - I like to minimise setup fussing.  If you were to get a platform, and say think you might upgrade to a 16" in the future, bear the weight spec in mind when looking around at platforms.

Best of luck,

-Niall

 

[hubble space telescope]

thank you!

but did you saw the objects good? like galaxys and nebulas?

[John]

3 hours ago, hubble space telescope said:

thank you!

but did you saw the objects good? like galaxys and nebulas?

I think the views of galaxies and nebulae that the 250px that Niall refers to will be very similar to the views that you can get with your current 10" dobsonian, unless yours has some problems or issues that you have not mentioned.

[niallk]

Hi again Hubble,

My 10" gives what I consider to be great views: the biggest factors for me that make a great night are darkness & sky conditions .  As John says, barring any issues with a scope, a 10" shows just loads 

If you mean comparing 15" vs 10", then yes a very noticeable enhancement. On paper it's nearly 1 magnitude. In practice, the first object I looked at was M81/82, and I muttered a 'wow': M81 was huge compared to M82 - I had a transparent night, and saw the outer spiral arms for the first time, not just the core region.  M82 was brighter than ever for me, and lovely details in its mottled core region.  From spiral arms in M51 to lovely views of the Sombrero, the Needle, the Black Eye... love it.  All visible with a 10" of course, but better where I live with the 15".

Globs significantly benefit from aperture - vastly enhanced.  Planetary nebs benefit from image scale, appearing bigger and brighter.  I've only really seen colour before in M42, whereas now I detect colour in several nebulae. Speaking of M42, I've only ever seen E and F in the Trapezium with the 15", and saw increased fine detail in dust filaments and the nebulosity.  I saw the ansae in the Saturn nebula, and hints of structure and beautiful green-blue colour in the Cats Eye and the Eskimo.

I also value the additional light gathered when using an O-III filter comparing at the same mag as the 10".

Star colour is also much more noticeable, as is detail & colour on Jupiter, and banding plus darker polar region on Saturn. I've had my best view of Mars with my 15", and I believe I caught 4 moons of Uranus.  I find that I push the magnification higher with my 15" than I do with my 10".  The moon is great too. Blinding, but superb details 

Coupled with better views, my 15" is just a joy in use because it moves so smoothly compared to the 10", and is a very rigid structure. It makes a dramatic difference in use particularly when tracking manually at moderately high mags. Don't get me wrong, the 250px is the best money I've spent on astro kit, no doubt whatsoever, and I highly recommend it.  But tbh I rarely use it now that I have the 15", even though its mirror takes much longer to cool down: just means planning ahead a bit.  Setup and take down is a bit more effort than the 10", but it takes <5mins. I hardly ever need to collimate the 10", whereas I do it every time I set up the truss 15". Collimation with a barlowed laser in the dark takes only a minute: no big deal.

Hth,

-Niall

[jetstream]

As an associate member of the dob mob ( I hope) I can say that DSO will show very well in smaller dobs, or bigger dobs or medium dobs.... dark skies are what really matter and observer experience.

Mapstar rightly points out how increasing aperture helps with the views through the link to Peach's excellent article.

I must say though, despite my association, my 2 refractors of 90mm and 120mm aperture work extremely well on DSO with the SW120ED giving me a hint of the Pleiades Bubble the other night.

 

[jetstream]

5 hours ago, hubble space telescope said:

thank you!

but did you saw the objects good? like galaxys and nebulas?

A 10" dob is an excellent all round scope if cooled and well collimated. In dark skies a 10" with show M51's spirals, M33 spirals, Pickerings Wisp in the Veil nebula.... Cassini on Saturn, GRS, barges and festoons in color on Jupiter...

An important thing is to match the scope to the targets, if you are really into astronomy- large targets, wide FOV etc. But really your 10" should provide excellent views of everything.IMHO.

[hubble space telescope]

thank you very much for your answers, but i think i'll buy a new telescope

another question that bothers me, is if i will connect my telescope to the phone/tablet/computer or any electronic device, does viruses can infect my telescope? 

 

      

[alanjgreen]

I wouldn't worry too much about this.

I could worry that "If i walk down the road a bus may run over me." but I don't  

stuff happens!

I haven't heard of scopes being infected. The software is just basic motor control stuff. you can just reflash the software if you have to.

buy what you want and enjoy it, don't let thoughts of what others may/may not do spoil your fun! You're only here once, make the most of it  

Alan

 

[hubble space telescope]

thank you alanjgreen, yolo

i understood that you can also choose an object from a software and then the telescope will go to the specific object, i dont know if it is releated to the motors but it sounds very cool.

i just want to be sure that if i connect my telescope it will not get infected by viruses... 

[mert]

My favourite scope was my 12" GOTO Skywatcher, more managable than my big dob and it was used a lot more.

[hubble space telescope]

and sorry that i have all the time a new question, but i read on the internet about a hyperstar...

i understood that it is good for long exposure astrophotography, but if i buy the wedge instead it will be good as the hyperstar or less good? and what should i buy between them? or there is a other or diffrente platform that's good for long exposure like the wedge or the hyperstar?

thank you very much for all you helps!!!!!!!!!

and all the answers, i really appriciate it!

[Davey-T]

2 hours ago, hubble space telescope said:

and sorry that i have all the time a new question, but i read on the internet about a hyperstar...

i understood that it is good for long exposure astrophotography, but if i buy the wedge instead it will be good as the hyperstar or less good? and what should i buy between them? or there is a other or diffrente platform that's good for long exposure like the wedge or the hyperstar?

thank you very much for all you helps!!!!!!!!!

and all the answers, i really appriciate it!

Don't mess with Hyperstar 

Dave