getting bigger images on my Meade 127 APO

[mindburner]

At thge risk of running before I can walk, I have had some limited success in imaging and was wondering if I can increase the size of say the whirlpool galaxy in my images. It came out very small indeed.

I was thinking about using a barlow but I understand that this will effectively double the F ratio. So my F7.5 becomes F15 which requires much longer exposure times and super precise tracking, which is probably beyond me and my current kit.

I am using a Nikon D5000 DSLR, would a dedicated astro camera give larger images due to smaller chip size?

My current setup is

NEQ6

Meade 127 APO

ST80 & QHY5/PHD

EQmod & laptop

Nikon DSLR

any advice much appreciated.

[Merlin66]

The size of the image (of a galaxy etc) is fixed by the effective focal length of the telescope, nothing to do with the size of the camera or the CCD chip.

If you do want a larger image scale, then, yes, you do need to increase the focal length ie barlow/ Powermate etc.

[mindburner]

thanks Merlin, I have just re-read my post, it's obvious to me now that the chip size will not increase the size of the galaxy, maybe just limit how much I can fit on perhaps. Just getting a bit confused

[Cornelius Varley]

Try this Field of View calculator to see how the image size changes relative to the size of the sensor.

Peter

[Merlin66]

Check out Craig Stark's freeware CCDCalc.

It will quickly show the image scale for various combinations.

[mindburner]

many thanks guys will check out the two sites