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Using the ST80 to seek out southern galaxies

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#1 tnakazon

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Posted 09 December 2012 - 12:12 AM

Took the Orion ST80 out to my Malibu site (orange zone) to seek out some faint fuzzies. Humidity was high, but I was still able to see the following:


1) NGC 7507 in Sculptor (visual 10.8, s.b. 12.9, size 2.8 x 2.7) using Expanse 6mm EP.

2) NGC 7176 in Piscis Austrinus (visual 11.2, s.b. 10.9, size 1.0 x 0.8) using 2X Barlow and 6mm Expanse EP.

3) NGC 7173 in Piscis Austrinus (visual 11.2, s.b. 11.2, size 1.2 x 0.9) using 2X Barlow and 6mm Expanse EP.


High surface brightness of these galaxies helped, along with an absence of sky glow above the southern horizon because of the Pacific Ocean. Of course there were others with just slightly lower visual and surface brightness (but were higher up in the sky) that I couldn't detect with this scope, no matter how hard I tried:


1) NGC 7252 in Aquarius (visual 11.7, s.b. 12.8, size 1.9 x 1.6) - tried on 2 separate sessions

2) NGC 309 in Cetus (visual 11.6, s.b. 13.6, size 3.0 x 2.5) - tried on 3 separate sessions


I used the stock star diagonal that came with the ST80 on all these sessions. Without having to move to a darker sky site, next time I'll use my dielectric star diagonal to see if it makes a difference. Less humid conditions would help as well.

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#2 IVM

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Posted 09 December 2012 - 07:14 PM

Nice setup and some unfamiliar objects! For 7252 I have Vmag 12.1 - probably doable under good conditions with 80 mm but by no means easy.

#3 tnakazon

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Posted 10 December 2012 - 10:52 AM

Thanks, I'm going to try again tonight (NGC 7252) - with less humidity projected and dielectric mirror diagonal.

#4 tnakazon

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Posted 11 December 2012 - 11:19 AM

Tried NGC 309 again last night using a dielectric diagonal on my ST80 but still couldn't detect it. So I tried using my 100mm Orion SkyScanner mini-dob - thought I caught a glimpse of it twice, but couldn't really confirm the sighting.

The views through the ST80 & SkyScanner are almost identical, despite the latter's 20mm of additional aperture. Maybe just a tad bit brighter view through the SkyScanner, but objects look a wee bit sharper with the ST80. Both scopes are flocked with black adhesive felt and were reasonably collimated. The focal lengths of both scopes are identical (400mm), so the same eyepiece used yields the same magnification.

Attempted NGC 7713 in Sculptor (visual 11.2, s.b. 13.3, size 4.6 x 2.2) with the ST80 only. Fairly low in the sky from Malibu (Los Angeles). Thought I glimpsed it using the 6mm Expanse, but couldn't confirm. Might have detected it with more certainty had I used the SkyScanner.

Also tried NGC 428 in Cetus (visual 11.2, s.b. 13.8, size 4.1 x 3.1) with both scopes. Higher in the sky and sandwiched between two stars, but couldn't confirm sighting in either scope using a 9mm or 6mm Expanse or adding a 2x Barlow with the 9mm.

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#5 IVM

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Posted 11 December 2012 - 11:31 AM

This is an interesting selection of objects. Why these galaxies, may I ask?

#6 tnakazon

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Posted 11 December 2012 - 01:54 PM

Good question!

I've already observed the brighter ones in this region, mainly with the SkyScanner. These are more difficult, at the limit of visibility with my 3.5-4 inch scopes.

I like seeking out galaxies.






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