centering objects

[alacant]

Hi

I'm a few sessions down the way from my first photo. No problems with brighter objects but the dimmer ones are a problem to know when you've nailed the centre fov. I've been trying to jump through hoops with a flip mirror but it won't work with my flattening lens. I'm not that interested in hooking up a computer and hit and miss with a short test exposure doesn't grab me either. My photos are more a record of where I've been rather than precision works of art.

I wondered what methods we used here. In the end, I think the simplest solution would be to mount and align a bigger finderscope. ATM I've an 8x50. I've also a old 80mm f5 which I'm thinking of using. Dunno. Any shared experiences would be most gratefully receieved.

Cheers and clear skies

[Tinker1947]

I use a 250mm Reflector for imagine and a ST-80 - Lodestar for guiding, the ST-80 is aligned precisely with the 250mm so EQMod synced with nearby Stars i extend the Lodestar to 5 seconds and finely centre any DSO i'm after and just image the DSO normal 20 minute exposure work nicely with objects centered on the CCD Sensor, it does of course require a PC with out one i would be there for maybe a hour looking for them.

NGC 891 @ 1200 seconds single image

[ollypenrice]

I just use the CCD camera in binned mode and an exposure of up to a minute or so if the object really is a faint one but normally five seconds is enough. This means a PC is essential.

Olly

[Davey-T]

Nice pic' Ray, have you tried finding things with the SW Star Adventurer ? took me quite a while to find Kembles Cascade with a 300mm lens the other night

Dave

[Tinker1947]

I use a 100mm F2 lens so it not so bad but it is just a point and shoot for the dim stuff......

[michael8554]

Hi alacant

A lot depends on what equipment you have.

A long focal length OTA on a non-GoTo EQ mount with small setting circles - very difficult without a PC to download images to, so that you can stretch your test shots and/or platesolve. A long exposure at maximum ISO, you might have enough data to see your target on the DSLR's LCD screen.

But you don't want a PC.

Most GoTo mounts can be SYNC'd on the nearest star you can navigate to and centre, then a GoTo your target may well be successful.

Flip mirrors are great for centreing bright planets onto tiny chips, but many DSO's are too dim for an eyepiece, unless your site is very dark.

I've never seen a DSO in a finder. For instance, with a 9x60 I can see Sheliak and Sulaphat, but not M57 inbetween them - 70 year old eyes perhaps to blame?

Michael

[Pompey Monkey]

Plate solving will get you to within a handful of pixels every time. There are a multitude of plate solving solutions out there if you use a PC/laptop to control your mount: Astrotortilla; Platesolve2 and ASPS are just three that come to mind. Many of them are free!