questions about future investments in astrophoto and random stuff

[piwko]

hi there!

thanks to all of you who will spend some of their time to help me

as long i as remember outerspace was quite intresting object to look at, now im thinking about buying some equipment no rush of course, i dont have tons of money so i want to spend them carefully

i started with canon 600d - utility, a good dslr is always usefull. In addition i have t-ring, t-adapter, remote shutter (were in bundel)

i borrowed celestron powerseeker 114/900 from my friends, set up, aimed the moon, sharp razor vision - wow. Immiediety atached dslr and found my 1st problem - can't reach focus, focus point is too deep in tube, then i tried with barlow 3x i was able to get focus, but that ''focus '' was realy dissapointing

example: http://postimg.org/image/bxf4o6p1r/

1st question. where was the problem in that photo? and whats that strange halo on the right side of moons edge? is it coma aberration? it wasnt visible with eye observations.

afocal photo with smartphone had better focus: http://postimg.org/image/k7cld0ujt/

2nd question. i was wondering what to chose - bigger newton like 150/750 sw or smaller 80ed, what would you grab in first place and why?

3rd quetion.  in some point in future i could try deep sky astrophoto so i need a equipment that can be guided, I know how it works, but i saw that some mounts have guider port, some of them dont. if i buy for ex. eq5 with 2axis drive where do i connect that guider feedback? ive read a lot bout astrophoto in this week and i got lost so that im asking rather that buying and then realeaseing that not what i wanted

4th. how to judge if telescopes focus point is too deep in tube so dslr cant reach focus?

thanks for your help

[Essex nightsky]

Hi and welcome.. Questions 2and 3 are best left to one of the many advanced users, I'm sure one will be along soon.

Question 1 chromatic abberation (the Barlow) inability to focus red and blue wavelength at same point. Easy fix netter barlow

Question 4. It is not uncommon for Newtonian reflectors to have focus issues with dslrs (search infocus problems ect) basically the focal point is too close to the primary mirror, therfore secondary as well for the dslr to reach, the symptom will be unable to reach focus (depending on how far off it is, you may notice it getting better and better as it travels inward but not quite reaching focus)

Hope this all makes sense and an experienced member will surely be here to help with 2&3

Grant

[damnut]

Hi There,

Warm welcome to SGL.

The focus for this scope is as you guessed beyond the focal point of your camera. Before spending more cash on hardware do buy a book called making 'every photon count' this is a well respected guide to astrophotography.

The choice of scope is secondary to the mount, but the 80ed has a great reputation on the forum. I would also say go along to a meet of your local astro group and see what others have and what may suit you best.

[Blazar]

Hi there...I see question 1 is sorted (and yes its CA). most Doublet refractors suffer with this (including my TALS's). you can get filters to help reduce it, but to be honest I don't use one.

Question 2 is really dependent upon what you wish to do and see (or image). I like imaging the moon and planets. Therefore I chose a scope that had a good reputation in that arena (long focal length SCT). it is also a nice visual scope. I have many scopes now that really have different uses and combining them with different cameras give other results. As I said, might be good to sit down and work out exactly what you want from the hobby, then look at the equipment used by members on this forum (or as previously noted, a local astro club)

Question 3....most new mounts have a guide port (if buying second hand then some investigation will be needed). Guiding brings other challenges..you then need a guide scope / camera that also needs powering etc..then the laptop to run the guide software). I have just started to try guiding...had the equipment for a while, but keep being distracted by planets ;-), and I don't need guiding for those! You still need to go through polar alignment even if guiding...don't be deceived that you can just point and a star and follow it....takes a bit of practice. I would get a mount with the capability, but not start off  by guiding...its a steep enough curve before you add it into the mix.

I would also recommend the imagers bible (if that is what you are interested in) called "making every photon count" by Steve Richards. its an excellent resource. Another one is turn left at Orion...purely for telescope maths....

You won't go far wrong if you follow your interests....but then there is always something else to buy ;-)

Regards

[Joseki]

yes, definitely pick up  'every photon count' .  However, I can spare you some time and tell you it recommends buying the best mount you can afford and a HEQ5 as a minimum.  

eq3-2 and eq5 mounts can be guided if they're the pro versions (with goto) but they're not as good mounts.  As a rough guestimate though for a total kit,  going 2nd hand, expect to pay £500 for a HEQ5.  For scope, the cheapest favourite here is a skywatcher 130pds (should have no problems reaching focus with a DSLR with that reflector), ~£120 2nd hand if you can find one.  Then you'd need a coma corrector ~£70-100.  Next a guide camera, can be had for around £100 2nd hand, convert a 50mm finderscope for a finder guider and get a cheap windows laptop ~£150 2nd hand.   - which is pretty much a decent beginners rig, total cost around £1000 (plus DSLR). 

[piwko]

thanks for all answers

I was thinking about buying that book, probably i'll do it this week, and as i metioned before i have time so i can slowly build up my equipment so that's why im asking.

one more question, do xED scopes need coma corector like newtons?

[RikM]

The ED80 doesn't need a coma corrector, but does need a field-flatner/focal reducer instead.

[hjw]

Hi,

I have been in your position about half a year ago. What I have learnt is that the mount is the heart of the setup. If you can be patient and save a bit longer and go for the HEQ5 rather than the EQ5 you will have the better option. You can guide the EQ5 through the serial port of the hand-controller using software like EQmod, while the HEQ5 has a dedicated port for guiding. In terms od scope it is dependent on what your preferred targets are. I like nebulae (bright and colourful) and they are big! The SW ED80 is a great scope for this. Galaxies are a bit trickier (smaller and fainter) and would ideally require a "faster" and longer reflector (e.g. 8"; f/5). And finally the ED80 is not really suited for planets. A much longer focal length would be beneficial.

Unfortunately there is no one solution to fit them all and you will see in the signatures of more experienced astrophotographers that they have multiple scopes - YOU HAVE BEEN WARNED

[swag72]

Getting hold of the book 'Making Every Photon Count' as said is a good place to start. Then read it once...... twice ...... and thrice........ by then you should have an idea of what you need and more importantly why you need it. Then you are set to start thinking about purchases!!

Mount...... mount ...... mount ...... for DSO imaging. Try to scrimp and save on the mount at your peril, you will only have to buy twice. The HEQ5 is a good starting mount, and has been the basis for many a good imagers kit. People will say that you can do it with less (An EQ5 for example) and yes you can..... but you will throw away significant numbers of subs due to it not really being up to it. And interestingly enough....... almost all of the folks who say that they have fettled their EQ5 and how well it works appear to jump ship to an HEQ5 or better if given the chance.

Have a look around the imaging section, look at peoples images as they generally say what kit they used. This will give you some good ideas. Be realistic with what you want to achieve. If you are on a budget then be aware that some peoples kit cost more than the price of a family car.

Then there's the processing - This can take longer than the data capture itself and I think often gets overlooked. I reckon that processing easily makes 80% of the final picture. The data capture can be a long and boring road..... it's the processing that makes the picture

All in all, have fun and enjoy it................ there's a load of people out there with experience and who will help where they can