TeleVue ParaCorr Type 2 Coma Corrector - Visual Use Review

[jam1e1]

Hi,

Received this from fellow SGL member (thanks), bought for use in SW 250pds Newt F4.7.

Was looking for something that would be easy to use, gave visual pinpoint-ish stars across the EP and didnt degrade view in terms

of dimming stars.

Justification for buying was having owned a number of 'barlows' from cheap out of box to the 2.5x TV powermate, TeleVue in my

opinion has been the top performer by far, in terms of value for money and quality of view in the 'accessory' category.

Note whilst in my view TV win in 'accessory' field, when comes to EP and value for money, I dont neccessarily intend to own full range

of TV EPs, considering can spend far less on close contenders, hence to be clear im not TV 'all the way'

Targets: Jupiter & Moons, Starfish Cluster, M35, Mel 20, Pilades

EPs tested: Meade 5000 UWA 8.8mm 1.25", 24mm 2", TV Nagler 12mm 1.25"

21/11/12 around 10pm, moderate Light Polluted skies - note this has only been tested on one night so far. Left scope to cool for

~30m, collimated and tested with laser collimator.

Results

Jupiter with 8.8mm & 12mm

Overall didnt really appear to have much, if any, effect on Jupiter itself, although the moons were slightly sharper, more

noticable effect on the 8.8mm.

Pilades with 24mm

This test was to measure effect of star brightness and sharpness. Without CC there was noticable coma towards outer edges, getting

worse further from centre. The CC addition did noticable improve the view and certainly gave sharpness right towards edges, only

as good as centre star got. Noticed the slight barlow effect in terms of magnification but wasnt offputting. right at edges there

was some coma but then again, its not a magic bullet, and to be expected

Starfish

24mm - The CC certainly added a good level of correction right across the field. Without the outer 70% stars had noticable coma

getting worse as went out, was pleased with effect the CC had and certainly added to sharpness right to near edges.

12mm - thought the view was good without CC, with CC this added some level of correction but not as noticable as the 24mm

8.8mm - again this was quite close up view, good improvement overall, though was quite high mag so didnt expect a dramatic result

M35 - This was to test effect of adding CC and reducing visual magnitude as had good range bright and dim stars

24mm - with CC added good correction to edges and from near centre, when comparing to without, no noticable drop in star

brightness

12mm - focussed my eyes on some very dim stars barely viewable near centre, better seen with averted vision. Compared number of

times with and without CC, really didnt notice any effect on brightness hence glad to say didnt appear to dim the view. Again

correction less noticable as already well corrected, but did add subtle effect.

8mm - again on above test, similar result. Correction again good, although the wider EPs did appear to have more noticable effect

on correction.

Mel 20

24mm - With CC really did add good level of correction to stars middle to outer edges, swapped CC in and out number of times

looking at certain parts of FOV, noticable improvement

12mm - again less of delta but did add small level of correction

Conclusion

To summarise only personal 'negative', if any, is the slight barlow effect hence slightly reduces FOV, but by very little.

Another point to note is need to pull the CC out slightly depending on EP used as different focal points, no EPs appeared to focus

with CC fully inserted into focuser, but to be honest wasnt really an issue.

Build quality is solid, adjustment is straightforward and 'fluid' type feel when adjusting.

As expected the visual improvement will only be as good as how the centre EP star appears in EP without the CC - what I mean is it

wont give 10" frac type views if warm scope/mis-collimated/bad seeing etc - if the centre star is blurry then thats as good as

rest of stars will be.

Colour correction appeared to be good and no noticable negative effects e.g. CA

TV EPs appear better corrected in first instance hence effect is less noticable, for 'cheaper' eyepieces the effect of the CC is

more noticable and larger 'delta' effect. TV EP changes less but still subtle improvement.

Overall does what it says on the tin and does noticably improve view for me, although more with lower mag EPs. Also acts as a nice 1.25"/2" adapter with compression rings so doesnt damage EPs.

Will be keeping - just need to redo EP case now & try to fit in!

[swamp thing]

Nice one Jamie. Look forward to having a butchers next time we meet up. I'd like to try my Terminagler and see how that looks if that's okay?

[jam1e1]

Course always welcome, interested to see how performs on other ep and scopes!