Christmas Comet

 

Comet 8P Tuttle – has been seen for virtually every return since its discovery in 1790 by P. Méchain. However, the short period (13.95 years) of its orbit was not initially recognised so when Horace Tuttle found a comet on 5th Jan 1858 it was not recognised as the same comet so his name not Méchain's was given to the comet. 

 

Interestingly since it will be visible on 5th Jan 2008 it will be exactly 150 years since Tuttle first saw it. Also provided the comet reaches its predicted brightness of +5,7 it will be one of the brightest appearances since 1871.

 

The comet track starts by making a loop around Polaris passing only 1.5 deg from it on 5th October. Note, it will be very faint at 14th mag. The good news is it's on its way towards the Earth and after a slow start it brightens rapidly from +10th mag on 26th Nov becoming naked eye (+6th mag) on 28th Dec.

 

The highlights of the track are when it passes through Cassiopeia, comes within 6 deg of M31 - Andromeda Galaxy (28th Dec) and passes in front of Galaxy M33 (30th Dec). The comet is finally lost after 12th Jan in Cetus.

 

As an added bonus on 22nd December the Ursid (Ursa Minor) meteor shower takes place. The meteors are debris from previous passes of Comet Tuttle.

 

It is not often a comet is so well placed as to allow it to be followed closely for several months. The Centre will be making the most of this return. Please return to this page to watch progress or better still make a booking and see it for yourself through our 16 inch telescope.

 

This is the best time to see this comet, as its next return in 2021 is not favourable for the UK.

 

OBSERVATIONS

 

Comet 8P Tuttle

Date:     11th / 12 November 2007

Time:     22.00UT

Description

The first frosty night of winter gave a transparent sky for hunting down Comet Tuttle while still a faint object. Right on track 2 deg south of Delta Umi was the faint oval fuzzy object of approx. mag +11.5. The comet has a slightly brighter condensation at the centre.

 

Update

Date:     28th / 29th November 2007

Time:     19.00UT

Comet Tuttle creeps ever closer to the Earth, having completed its loop around the Pole Star (Polaris) is on its way to Cepheus. Located 5 deg NE of Polaris the comet was quickly found in the 10 inch Dobsonian. Appearing as a +10th mag smudge very similar to many Messier galaxies.

 

Update

Date:     8th / 9th December 2007

Time:     20.00UT

Comet Tuttle moves from Ursa Minor to Cepheus. It was 2 deg east of 3 Ceph (Errai), still a relatively faint +9 mag. The core is still an indistinct.

 

Update

Date:     28th / 29th December 2007

Time:     21.00UT

Comet Tuttle moves Andromeda having passed M31 Galaxy. An easy object in binoculars – it appears as an oval smudge with a bright star-like core.

 

Sadly, we have now lost this comet from northern skies.

 

 

Comet 17P Holmes

Wide Field View
 

Track of Comet
 
Edwin Holmes discovered this comet in Nov 1892 when it suddenly brightened. Normally the comet is very faint +17 mag due to its great distance of 2AU (300 million Km).  Between 1906 and 1964 it was not seen at all. It takes 6.9 years to orbit the Sun. In July 07 the comet was seen at +15 mag and fading when suddenly comet has gone into outburst again sending its brightness rocketing from + 3 mag in only 12 hours on the 24th Oct. It has continued to brighten as the coma expands, but seems to have stabilised at +2.5 mag.

 

Located west of Perseus it is now visible to the unaided eye as a new star. Telescopes show it as a yellow planetary nebula like object.

 

Since we do not know the reason for the outburst it is too early to say how fast it will fade, but following the 1892 event the comet was easily visible for several weeks.

 

The comet has been expanding at a rate of 0.5km/s  (1,100mph). While the actual nucleus of rock and ice is estimated to be only 3.5km (2.2 miles) astronomers from Hawaii on 9th November 2007 estimated the diameter dust coma to be 1.4 million km (0.9 million miles) across. Remember it has not stopped expanding yet!!

 

Events like this are why I do astronomy – something amazing will always happen eventually.

 

Click on the images for locations maps. Note the comet is brighter than all the stars immediately around it.

 

OBSERVATIONS

 

Comet 17P Holmes

Date:     26th / 27th October 2007

Time:     20.30UT

Description

Finally, we had our first view of this intriguing comet. As the clouds parted the star-like nature of the comet was obvious to the unaided eye, but a look through binoculars showed it was far more. First telescopic view was through the 10" Dobsonian. The comet differs from earlier descriptions of being large fuzzy ball – now it has three distinct parts. Though visible in the 10" the following features were more distinct in the 16". A moderately bright ring with a wispy edge (reminds me of a circular saw blade) an inner brighter and more dense circle finally a very bright pin point nucleus offset near the edge of the dense layer. The nearby stars of alpha Per (+2mag) and delta Per (+3 mag) show that the comet is approx +2.5 mag. The diameter is estimated at 4 arcmin. The brightness really shows up as the picture was taken with a simple

 


Nikon Coolpix 775 digital camera on auto.  Remember all this was seen and imaged with a nearly full Moon not far away!

 

Update

Date:           28th / 29th October 2007

Time 22.30UT

 

The comet maintains its brightness. Having observed 20+ comets it is hard to put across how different this one is. Plus how it differs to all the brighter deep sky objects – at low power globular clusters look granular, while nebulae or galaxies look translucent. The combination of large diameter and bright opaque disc make this standout as unusual.

 

Two obvious developments are 1) the diameter has grown – now estimated at 6 arcmin overall, the brighter inner disc is 1 min arc; 2) the outer ring is not evenly bright anymore – the sunward half is still bright, but the opposite site is fainter due to the dust cloud thinning (?).

 

As the comet passed a nearly star (HU209) by chance it almost exactly matched the magnitude of the core.

 

Update

Date:     3rd / 4th November 2007

Time:     19.30UT

Even to the seasoned observer the first thing you think when you look through binoculars is WOW. The comet shows no sign of slowing down its expansion. It is now a staggering 15arcmins at the current rate it will reach the size of the full Moon within 10 days. There are some signs that a tai is forming, but it is pointing away from the Earth.

 

Update

Date:     8th / 9th November 2007

Time:     19.00UT

Now nearing the size of the full Moon – the increase in size has caused a decrease in brightness to magnitude +3. The D shape appears more defined with faint extensions hinting at the tail that is starting to show up in long exposure images.

 

Update

Date:     13th / 14th November 2007

Time:     21.00UT

Thus amazing comet is still growing (now approx 50 arcmins) – it has been described as looking like a jellyfish. It is well defined at the front though developing a more oval shape. At the back the coma fades away into the background of the Milky Way. The bright nucleus has faded so it is only slightly brighter than the surrounding central coma. Streamers of material are stretching away from the nucleus. Faint stars are visible through the comet.

 

Click on images to see enlarged views

 

Update

Date:     13th / 14th November 2007

Time:     21.00UT

One month after its unexpected outburst the comet is no longer the eerie glowing blob, but even low power binoculars still show that the largest object in our Solar System (it's nearly twice the size of the Sun) is still a spectacular object.

 

Update

Date:     28th / 29th November 2007

Time:     18.30UT

With the overpowering Full Moon gone there is still plenty of Comet Holmes to see. It still remains ½ deg across and easily outshines the Andromeda Galaxy. The bright jet from the centre has thinned, but remains prominent.

 

Update

Date:     10th / 11th December 2007

Time:     18.00UT

Holmes is still expanding though much more slowly than before. It has reached a staggering 1¼ deg across. It is quite translucent with even faint stars shining through. The central bright jet is still prominent.

 

Update

Date:     28th / 29th December 2007

Time:     21.00UT

Surprisingly, Holmes still remains just visible to the unaided eye. It is now much more transparent as the dust cloud disperses. Similarly, the central jet has also faded.

Comet Holmes and Comet Tuttle are only 22 deg apart.

 

 

 

 

Comet F1 Loneos

As a prelude to Tuttle we also have another comet - F1 Loneos reaches +10th magnitude on 30th September 2007 as it passes into the Coma Berenices Cluster. It will become naked eye visible (+6th Mag) by 22nd October.

This comet is not quite so well placed as it remains in evening and morning twilight most of the time.

 

OBSERVATIONS

 

Comet C2007 F1 Loneos

Date:     9th / 10th October 2007

Time:     19.28UT

Description

The comet is 4 deg west of the Coma Berenices Cluster and at the time observing only 6 deg above our horizon. It appears as a small round fuzzy ball estimated at magnitude +7.5 – reports are it is brightening quicker than predicted. Through so much atmospheres an accurate estimate of brightness is difficult.

Update 17th October 2007

Comet F1 has been observed over several nights and is still brightening - it is now an easy object in binoculars. In our 10 inch scope it shows a bright nucleus and elongated coma. Current magnitude is estimated at+6.5. The comet is closing on Eta Bootis (Muphrid). The comet can either be observed after 05.00UT in the east or 19.00UT in the west.

 

Update 22nd  October 2007

The comet is showing a more oval shape with the nucleus more to one side indicating a larger tail is developing.

 

This comet is now lost to Northern observers.