I can't see Polaris or Octans for polar alingment

[Brian W]

Hi All, I live in the Philippines and neither Polaris nor Octans are visible from my location. If I buy a Celestron Nexstar 4 SE 102mm F/13 Maksutov-Cassegrain go-to will I be able to align it accurately enough with the alt-az alignment to do multiple exposure / long exposure photography?

Brian

[bojan]

Drift alignment is applicable to any location on the planet.
Also, there are applications that will guide you through process of alignment...

[Brian W]

Hi Bojan, I understand that drift alignment is world wide. My question is 'if I use 'Sky align' which works with the alt / az rather than the polar alignment because I cannot see either Octans or Polaris from my yard will I get an accurate enough alignment for multiple exposure astrophotography so I can stack in pp.
Brian

[sil]

look into solar noon aligning, its what I did and worked perfectly for me. I don't know if you can park your alt/az position into a repeatable position, but I could with my eq so I rough guessed and locked a bolt so the mount was positioned against it when I put it on the tripod and used solar noon to get me a north south line to set this position direction, then s digital level meter to set the inclination and when I photo tested a long exposure just assembling to this position the rotation center was in the central third of my frame. Then I would star align from there if I wanted. You may be able to work out something similar with yours and put ground marks for the tripod feet to match to.

[bojan]

I can't see why you should not ( stacking accuracy will depend on Focal Length of your system and exposure time).. however I can't say anything specific about that particular mount/application from my own experience... sorry.

[Brian W]

I did look it up and yes I can leave my set-up parked. This should work nicely. Thanks

[Brian W]

without the ability to stay focused on the same precise area nothing else matters.

[raymo]

Brian, The 4SE is not a good choice for deep sky astrophotography, because it is VERY slow photographically, and would need VERY long exposures for
just about all deep sky objects. It is however very good for lunar and planetary imaging, [much brighter objects].
With very long exposures [subs] you would need accurate polar
alignment, and guiding, which is not the 4SE's forte.
For long exposure imaging you really need an equatorial mount which
has hand operated adjusters on both axes, and a "faster"scope,
say between f/4 and f/8.
Sky Align, unless it has recently changed radically, is only accurate
enough to place a given target in the field of view of a low to medium
power eyepiece; it is not intended for imaging. For long exposure work
the mount has to be pointed to within a few arc seconds of the
celestial pole, far beyond the capability of Sky Align.
raymo

[Brian W]

Okay, bearing in mind that it is simply impossible for me to do a polar alignment and the best I can do is a solar alignment can you suggest any system for under 1000 that would work?

[raymo]

With an equatorial mount you can do an accurate polar alignment without
being able to see the pole, by using the DARV method of drift aligning.
You can google DARV by Robert Vice, and jot down the instructions. After a bit of practice you can get precise alignment in 15-20 minutes.
As for a suitable rig under $1000, the only arrangement I can think of
is a 6" f/5 Newtonian on an EQ3 mount with dual axis motor drives and a
single speed focuser from Andrews for $899 or $999 with a dual speed focuser. Unfortunately it is not Go-To, so you have to find your own targets. With the above mentioned rig you could get exposures of 45-90 secs without guiding.The 6" has good light grasp, so you could get nice results by stacking subs of that length.
Small refractors would do a good job, but non APO ones suffer from chromatic aberration, which is bad news for your images.
If you really want Go-To you could find used gear in our classifieds
section.
raymo

[Sato]

I know I must be missing something here, but why would you want to use Octans etc from a northern hemisphere country? Please put me out of my misery :).

[Brian W]

DARV I could do. I don't need go-to but I do need tracking and as I understand it they are a package deal? Long exposure and multiple frames is what I'm looking for.

[raymo]

No, not a package deal, all equatorial mounts with drives can track.
I think Brian was just illustrating his situation, in that he can't see either
pole.
raymo

[Londoner]

Just looked up his position on Google maps and he has a tough time seeing Polaris, which will be close to the horizon :eyepop:

Mick

[Londoner]

I'm a newcomer to astrophotography and I'm still accumulating equipment to begin.
However, I used Google Earth satellite view to identify a point where I can place my mount next to my home and another on the south axis across a valley. Fortunately, this happened to coincide with the edge of a building 2km away.:)
When I set my mount up I used the level app on my smart phone to give a reasonably accurate measurement for my latitude. When I hooked up Polemaster for its first trial run I immediately got Octans trapezium on the screen- infact Sigma was almost centre. Probably a lot of luck too I know, but Brian might be able to use Google Earth at least for an accurate north south alignment.

Mick

[Brian W]

I'm within 10 degrees of the equator. Octans and Ppolaris are just about even for me and neither is visible.
Save

[Brian W]

I have o cell phone, smart or otherwise but I'll give it a try.
Save

[chuckywiz]

I use software called alignmaster. Manually chuck in. A bunch of stars for your area. Or part of the sky you can see. I get great alignment in 10-15 mins stress free

Ben

[Sato]

I would never have known! :thanx:.