Advice for OTA n later become guider scope

[liquidice]

Is it good idea to get a small OTA as current scope. Later add in a big 8-9" OTA , and change the small one as guide scope?

Is it more important to have OTA or mount, covered with warranty?
Or neither also ok?
I m not from sg.

And if ok, which small OTA is good for this?
Orion St80?

Will cgem or cg-5 or atlas mount goto system work well with this st80 or similar?
Thx

[cloud_cover]

If you are thinking of Astrophotography, arguably the mount is far more important than the OTA. Most modern telescopes are decent for astrophotography but most mounts are less so. Having said that, most high quality mounts are expensive.
I have no experience buying in-warranty items. Personally my scopes and mounts have all been bought second hand either locally or on Astromart/Cloudynights.
I would suggest to look at your budget, then decide how much you should spend on each and whether you prefer to do photography or visual.
Regarding guidescope, don't worry too much. As long as you keep the main scope focal length below 1000, a 50mm guider is sufficient and is lighter and easier to mount. So buy an OTA that will meet your needs rather than one "for future guidescope use".
The ST-80 you have mentioned is a fine budget scope but being an Achromat, it is less useful for planetary viewing. Its strength is really in widefield views of stars and DSOs as the lower magnification reduces the false color seen. This, however, is best appreciated under dark skies. It is, however, useful as a guidescope.

[orly_andico]

the ST80 would make a pretty bad DSO imaging scope. I have seen results from this. The chromatic aberration around bright stars is very intrusive.

I would suggest as a small OTA get a William Optics 70ED. The new one with the digital focuser. Also get the matching flattener. You can use it as an imaging scope, and then later as a (very posh) guide scope. You could move the flattener to your new larger imaging OTA. Surprisingly the refractor flatteners work fine on SCTs.

[liquidice]

but no one selling the William Optics 70ED here second hand yet.
only the orion st80. maybe i will try look at cloudynight forum

but, is orion st80 good as guide scope anyway? or just ... so so only?
what if orion st80 as guide scope, and slr camera piggyback on it with 30mm 1.4 camera lens.
and get a cgem / cg 5 / whatever second hand mount for this above.
would that give me a better start? for my m42 first object

my budget, a..... 7200 SGD include shipping, tax, ....
include guidescope, mount, ota, goto, narrowband, .....all the necessary sets
after that , no more further spending for upgrade....
otherwise, it will be like SLR black hole, endlessly, never ending

[cloud_cover]

If you want I can sell you a Vixen SXD plus VMC200L plus dedicated 0.66x focal reducer for $4500 Comes with dual speed JMI focuser. That's an 8", flat field Cassegrain. With the reducer it becomes a reasonable 1200+mm at f/6.3 (I think). Note the SXD does not have a half pier - you may need it to prevent the counterweight pole from hitting the tripod legs
That leaves you with $2500 for shipping and guidescope/guider setup.

[liquidice]

I come over next week and u show me le
Pm me your contact
And address

[orly_andico]

if you want to do narrowband your budget is insufficient.

you need another $2000 US for an STF8300M which is the cheapest (big sensor) mono camera out there. plus the filters and filter wheel.

of course you could use just the mono camera and one filter on the nosepiece, and swap filters manually.

i'm looking for a mono camera myself but things aren't looking good. it was a mistake to buy a one shot color camera...

[liquidice]

i tot narrowband can be done by using ha and 2 other filter?

[orly_andico]

Yes. but you also need to buy a mono camera.

one shot color camera not ideal for narrowband because of the bayer filter. don't even think about using a DSLR for narrowband. it won't work. even a modded DSLR will be marginal. narrowband needs really long subs (10 - 20 minutes) which demands a good mount and good cooling.

the cheapest mono cameras with big sensor are based on Kodak TrueSense 8300 chip. cheapest 8300 mono camera is SBIG STF8300M. $2K USD right now with $500 rebate.